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PRINCIPLES 


ECONOMIC  ZOOLOGY 


BY 

L.  S.  DAUGHERTY,  M.S..  Ph.D. 

PROFESSOl!     OF    ZOOLOGY,  STATE    NORMAL    SCHOOL,     KIKKSVILLE,    MO. 

AND 

M.  C.  DAUGHERTY 

AUTHOR    WITH     JACKSON    OF    "AGRICULTURE    THROUGH    THE    LABORATOI 
AND     SCHOOL    GARDEN  " 


SECOND  EDITION.  REVISED 
WITH  301   ILLUSTRATIONS 


PHILADELPHIA  AND   LONDON 

W.    B.    SAUNDERS    COMPANY 

1917 


Copyright,  1912,  by  W.  B.  Saunders  Company.     Reprinted  May,  1915. 
Revised,  reprinted,  and  recopyrighted  September,  191 7 


Copyright,  1917,  by  W.  B.  Saunders  Company 


PRINTED    IN    AMERICA 


PREFACE  TO   THE   SECOND    EDITION 


The  authors  have  corrected  some  errors  that  crept  into 
',0Q  first  edition.  We  have  added  suggestions,  problems,  and 
(iitestions  which  we  hope  will  be  of  use  to  our  fellow  teachers. 
We  have  diligently  compared  our  text  with  the  latest  Ger- 
,.an,  French,  English,  and  American  Zoologies,  and  we  be- 
lieve we  have  given  the  correct  facts. 

The  Authors. 
September,  1917. 


iHtilo 


PREFACE 


The  authors  have  long  felt  the  need  of  one  book  in  the 
hands  of  the  student  which  would  give  not  only  the  salient 
facts  of  structural  Zoology  and  the  development  of  the  various 
branches  of  animals,  but  also  such  facts  of  natural  history — or 
the  life  and  habits  of  animals — as  to  show  the  interrelations  of 
structure,  habit,  and  environment.  For  we  lielieve  that  a 
knowledge  of  both  structure  and  life-history  is  necessary  before 
any  suggestions  or  discoveries  can  l)e  made  concerning  the  prin- 
ciples which  underlie  and  control  all  animal  life,  including  that 
of  man.  For  it  is  principles  and  their  application  for  which  we 
are  searching. 

This  book  is  an  attempt  to  supply  this  need.  It  is  especi- 
ally designed  to  accompany  the  "  Field  and  Laboratory  Guide" 
(Part  I). 

For  the  sake  of  the  natural  history  many  examples  have 
been  included.  To  reduce  the  size  of  the  book  it  has  been 
necessary  to  print  this  natural  history  in  smaller  type,  but 
that  in  no  way  implies  that  it  is  of  minor  importance,  and  it  is 
by  far  the  most  interesting  portion  of  the  subject.  The  scien- 
tific names  need  not,  in  all  cases,  be  learned.  They  have  been 
used  because  common  names  are  so  often  misleading. 


Much  of  the  subject  matter  has  been  derived  from  our  own 
observation  and  experience,  but  we  have  made  use  of  material 
from  all  available  sources  and  we  have  tried  to  give  credit  by 
continual  reference  to  the  authorities  used.  That  a  book  of 
this  character  can  never  be  original,  everyone  knows.  The 
scope  is  too  great  for  the  observations  of  one  lifetime. 

We  are  aware  that  we  have  fallen  far  short  of  our  ideal. 
But  we  believe  the  book  will  be  of  much  service  if  followed  as 
suggested  and  used  in  connection  with  Part  I.  "If  a  better 
system  is  thine,  impart  it  frankly.     If  not,  make  use  of  mine." 

The  Authors. 

KiRKSVILLE,  Mo. 


CONTENTS 


PAGE 

Branch  Protozoa  .  : 1 

Class  I.  Rhizopoda,  1. — Class  II.  Mastigophora,  4. — Class  III. 
Sporozoa,  4. — Class  IV.  Infusoria,  5. 

Branch  Porifera  . 10 

Branch  Ccelenterata 17 

Class  I.  Hydrozoa,  18. — Class  II.  The  Scyphozoa,  26. — Class 
III.  Actinozoa,  26. — Class  IV.  Ctenophora,  31. 

Branch  Platyhelminthes 34 

Class  I.  Turbellaria,  34.— Class  II.  Trematoda,  35.— Class  III. 
Cestoda,  37. — Class  IV.  Nemertinea,  39. 

Branch  Nemathelminthes.  . 41 

Class  I.  Nematoda,  41. — Class  II.  Acanthocephala,  44. — Class 
III.  Chffitognatha,  44. 

Branch  Trochelminthes  . .  .* 46 

Class  I.  Rotifera,  46. — Class  II.  Dinophilea,  47. — Class  III. 
Gastrotricha,  47. 

Branch  Molltjscoida 48 

Class  I.  Polyzoa,  48.— Class  II.  Phoronida,  48.— Class  III. 
Brachiopoda,  48. 

Branch  Echinodermata  .  .  .  : 50 

Class  I.  Asteroidea,  54. — Class  II.  Ophiuroidea,  56. — Class  III. 
Echinoidea,  58. — Class  IV.  Holothuroidea,  60. — Class  V. 
Crinoidea,  62. 

Branch  Annulata 65 

Class  I.  ChiPtopoda,  65.— Class  II.  Gcphyrca,  69.— Class  III. 
Hirudinea,  69. 

Branch  Mollusca 72 

Class  I.  Pelocypoda,  73.— Class  II.  Gasteropoda,  81.— Class  III. 
Cephalopoda,  84. 

vii 


Vlll  CONTENTS 

PAQE 

Branch  Arthropoda 89 

Class  I.  Crustacea,  90. — Suh-dass   iMitomostraca,  90. — Order 

I.  Phyllopoda,  90.— Order  11.  ( )si  racHhi,  to.— Order  111.  Cope- 
poda,  91.— Order  IV.  Cirripcdia  or  Haniaclcs,  91.— Sub-class 

II.  Malacostraca,  92. — Order  I.  Phyllocardia,  93. — Order  11. 
Decapoda,  93. — Order  III.  Arthrostraca,  102. 

Class  II.  Arachiiida,  103. — Order  I.  Scorpionida,  103. — Order 
II.  Phalangidea,  104. — Order  III.  Araneida  or  Spiders,  104. — 
Order  IV.  Xiphosura,  110. 

Class  III.  Myriapoda,  111.— Order  1.  Chilopoda,  111.— Order 
II.  Diplopoda,  112. 

Class  IV.  Insects,  112.— Order  I.  Ai)tera  or  Thysanura,  126.— 
Order  II.  Ephemerida,  127.— Order  III.  Plecoptera,  128.— 
Order  IV.  Odonata,  129.— Order  V.  Isoptera,  131.— Order  VI. 
Orthoptera,  132.— Order  VII.  Hemiptera,  140.— Order  VIII. 
Coleoptera,  148. — Order  IX.  Diptera,  153. — Order  X.  Siphon- 
apiera,  161.— Order  XI.  Lepidoptera,  162.— Order  XII.  Hymen- 
opt.era,  174. 

Branch  Chordata 188 

Sub-phylum  and  Class  I.  Adelochorda,  191.— Sub-phylum  and 
Class  il.  Urochorda  or  Tunicata,  192. — Sub-phylum  and 
Class  111.  Acrania  or  Amphioxus,  194. 

Sub-phylum,  IV.  Craniata  or  Vertebrata,  195. — Class  I.  Cy- 
clostomata,  195. 

Class  II.  Pisces,  196.— Sub-class  I.  Elasmobranchii,  206.— 
Sub-class  II.  Holocephali,  207.— Sub-class  III.  Dipnoi,  208.— 
Sub-class  IV.  Teleostomi,  209. — Order  I.  Crossopterygii,  210. — 
Order  II.  Chondrostei,  210.— Order  III.  Holostei,  210.— Order 
IV.  Teleostei,  211. 

Class  III.  Amphibia,  221.— Order  I.  Stesoccphala,  228.— Order 
II.  Apoda  or  Gymnophiona,  228. — Orddr  III.  Urodela  or  Cau- 
data,  229. — Order  IV.  Anura  or  Ecaudata,  233. 

Class  IV.  Reptilia,  236.— Order  I.  Rhynchocephalia,  238.— 
Order  II.  Ophidia,  239.— Order  III.  Lacertilia,  243.— Order  IV. 
Chelonia,  248.— Order  V.  Crocodilia,  253. 

Cla.ss  V.  Aves,  258.— Division  A.  Ealit(r,  27S.— Division  B. 
CariiuiloR,  2>>\.— Water  Birds:  Order  I.  Pvsoi^odes,  281.- Order 
II.  Lousipennes,  282.— Order  111.  Tubinares,  283.— Order  IV. 
Stc^anoiKides,  284.— Order  V.  Anseres,  285.— Order  VI.  Odon- 
tojilossa-,  2S6.— Order  VII.  Herodiones,  286.— Order  VIII. 
Paludirokv,  289.— Order  IX.  Limicola>,  290.— La«d  Birds: 
Order  X.  Gallina',  291.— Order  XI.  Columba;,  292.— Order 
XII.  Raptores,  294.— Order  XIII.  Psittaci,  297.— Order  XIV. 
Coccyges,  297.— Order  XV.  Pici,  298.— Order  XVI.  Machro- 
chires,  300.— Order  XVII.  Passeres,  300. 


CONTENTS 

Class  VI.  Mammalia,  311. — Order  I.  Monotremata,  319. — 
Order  II.  Marsupialia,  320.— Order  III.  Edentata,  323.— Order 
IV.  Sirenia,  325.— Order  V.  Cetacea,  326.— Order  VI.  Ungulata, 
329.— Order  VII.  Rodentia  or  Glires,  350.— Order  VIII.  Car- 
nivora,  356. — Order  IX.  Insectivora,  366. — Order  X.  Chirop- 
tera,  368— Order  XI.  Primates,  372. 


Theories  of  Development 382 

Questions,  Problems,  and  Suggestions 394 

Glossary 413 

Index 417 


"There  are  more  things  in  heaven  and  earth,  Horatio, 
Than  are  dreamt  of  in  your  philosophy." 

Shakespeare. 


PRINCIPLES  OF 

ECONOMIC  ZOOLOGY 


BRANCH  PROTOZOA 

The  animals  of  this  branch  are  one  celled  and  microscopic, 
or  very  small.  These  cells  may  unite,  but  as  the  union  is  not 
organic,  it  is  said  to  form  a  colony,  and  not  an  individual  animal 
as  is  the  case  in  the  higher  forms.  A  colony  may  consist  of  a 
few  cells,  as  in  Gonium,  or  of  many  cells,  as  in  Volvox. 

Since  protozoans  are  so  minute  and  their  soft  protoplasmic 
substance  is  so  easily  dried  up,  they  are  usually  aquatic,  but 
some  forms  are  parasitic,  while  others,  as  Amoe'ba  terric'ola,  are 
terrestrial,  but  these  live  or  remain  active  in  moist  places  only. 
Protozoans  are  most  abundant  in  salt  water,  or  in  stagnant  pools 
of  fresh  water,  and  are  found  in  almost  all  parts  of  the  globe. 

Since,  by  reason  of  their  simplicity,  protozoans  are  adapted 
for  living  where  other  animals  could  not  exist,  they  are  supposed 
to  be  the  oldest  or  first  animal  life,  and  it  is  believed  that  they 
existed  in  the  Archaean  time.    (See  Fig.  302.) 

Numbers. — There  are  many  thousands  of  species  of  these 
protozoans,  each  species  differing  from  all  others  in  some 
detail,  yet  all  agreeing  in  their  unicellular  simplicity.  Only  a 
few  of  the  typical  forms  can  be  mentioned. 

CLASS   I.     RHIZOPODA 

The  lowest  class,  or  Rhizop'oda,  is  represented  by  the  Amoeba 
(Fig.  1).  It  is  an  irregular  mass  of  colorless,  semifluid,  or  jelly- 
like living  protoplasm  destitute  of  a  cell  wall.     There  is  no  dis- 

1 


StaUOilk» 


2  BRANCH    PROTOZOA 

tinct  line  between  the  clear  outer  homogeneous  layer,  or  ecto- 
plasm, and  the  inner  granular  substance,  the  endoplasm.  Within 
the  endoplasm  is  the  nucleus,  a  small,  round,  denser  mass. 

Sometimes  the  contractile  vacuole,  a  clear  sphere  of  liquid  and 
gas,  appears,  increases  in  size,  then  contracts,  and  disappears, 
and  a  new  one  is  formed.     This  is  supposed  to  aid  in  respiration 


m 


5*.'A^ 


Fig.  1. — Amoeba  polypodia  in  six  successive  stages  of  division.     The  dark 
white-edged  spot  in  the  interior  is  the  nucleus.     (Schulze.) 


and  in  carrying  off  the  waste  products   formed  by  oxidation, 
such  as  carbon  dioxid. 

Motion  and  Locomotion. — Under  the  microscope  the  amoeba 
may  be  identified  by  its  movements.  The  body  surface  will  be 
seen  to  protrude  or  rather  flow  out  at  one  or  several  points, 
forming  irregular  lobes,  called  false  feet,  or  pseudopodia,  which 


RHIZOPODA  6 

may  be  contracted,  or  the  whole  body  protoplasm  may  flow 
along  after  them,  thus  producing  locomotion  as  well  as  constant 
change  of  form. 

According  to  the  experiments  of  Professor  H.  S.  Jennings, 
particles  attached  to  the  ectoplasm  move  forward  on  the  upper 
surface,  disappear  over  the  anterior  edge,  and,  as  the  proto- 
plasm flows  along,  appear  again  at  the  posterior  end,  to  repeat 
the  circuit,  showing  that  this  locomotion  is  a  sort  of  "  rolling 
process." 

Feeding. — As  the  amteba  flows  or  rolls  along,  if  it  comes  in 
contact  with  a  particle  which  is  unfit  for  food,  it  passes  by  or 
over  it,  but  if  the  particle  is  fit  for  food,  it  flows  about  and  en- 
velops it,  and  forms  the  so-called  food  vacuole.  As  this  food 
vacuole  moves  along  the  endoplasm,  the  digestible  part  of  the 
food  disappears  in  digestion,  while  the  indigestible  portion  is 
left  behind  as  the  protoplasmic  body  moves  along. 

Multiplication  in  the  case  of  the  Amoeba  is  b}^  binary  division 
or  fission  antl  by  sporulation.  This  becomes  necessary,  since 
the  entire  animal  is  but  a  single  cell,  and  all  the  functions  for 
the  whole  animal  must  be  performed  by  this  one  cell.  Hence, 
it  must  remain  exceedingly  small,  so  the  nucleus,  as  well  as  the 
body  substance,  divides  into  two  halves,  and  two  individuals 
result. 

Encysting. — Under  unfavorable  environment,  such  as  drouth, 
the  Amoeba  contracts  into  a  tiny  sphere,  becomes  encysted  or 
encased  in  a  horn-like  membrane,  and  remains  in  a  dormant 
condition  until  favorable  environment  returns  to  it,  or  it  is  trans- 
ported by  the  wind  or  carried  by  other  animals- — in  the  dirt 
which  has  clung  to  them — to  a  favorable  environment,  where 
it  bursts  its  cyst  and  resumes  active  life. 

The  Radiola'ria  are  marine  Rhizopoda  which  have  their  pseudopodia 
arranged  Hke  rays.  Many  of  these  forms  possess  a  silicious  shell  or  skele- 
ton, and  myriads  of  these  shells  are  found  in  rocks  of  various  geologic 
ages.  One  type  reproduces  by  swarm  spores,  the  original  nucleus  dividing 
into  hundreds  of  daughter-nuclei. 

The  Foraminif  era  are  Rhizopoda  whose  fresh-water  forms  have  chitinous 
or  silicious  coverings,  while  the  typical  members,  which  are  marine,  have 
calcareous  shells.  When  the  animal  dies  the  shell  sinks  to  the  bottom  of 
the  ocean.  Such  multitudes  have  existed  that  vast  formations  of  chalk 
or  limestone  rock  have  been  made  by  their  shells.  The  stone  of  the  Pyra- 
mids is  said  to  be  composed  of  fossil  Foraminifera. 


4  BRANCH    PROTOZOA 

It  is  said  that  in  the  bodies  of  some  Radiolaria  are  found  unicellular 
Algse,  or  microscopic  plants,  which  furnish,  even  in  this  low  stage  of  life, 
an  example  of  symbiosis,  or  the  living  together  of  different  kinds  of  organisms 
for  mutual  benefit. 

CLASS  II.     MASTIGOPHORA 

The  Eugle'na  is  a  representative  of  the  second  class  of  Pro- 
tozoans (Mastigoph'ora).  It  has  a  more  fixed  arrangement 
of  parts  than  the  Amceba.  The  cell  is  surrounded  by  a  delicate 
membrane  perforated  at  the  blunt  anterior  end  by  a  funnel- 
shaped  mouth  through  which  the  food  passes  into  the  body  sub- 
stance. From  the  base  of  this  mouth  the  protoplasm  extends 
out  in  a  long  flagellum  which,  by  its  lashing,  propels  the  body 
forward,  and  produces  currents  of  water  which  bear  food  into 
the  mouth.  Back  of  the  mouth  is  a  tiny  pigment  spot  beside  a 
clear  space  which  is  sensitive  to  light. 


CLASS  III.     SPOROZOA 

This  class  consists  of  parasitic  protozoans.  The  Gregari'na 
is  parasitic  in  the  intestines,  reproductive  organs,  or,  rarely,  in 
the  body  cavity  of  invertebrates,  such  as  crayfish,  insects,  and 
worms.  It  absorbs  liquid  food  from  its  host  and  has  no  mouth 
nor  pseudopodia.  One  or  two  individuals  become  encysted  and 
then  break  up  into  a  number  of  minute  portions  called  spores. 

The  Haemosporid'ia  are  sporozoans  which  live  in  the  blood-corpuscles  of 
vertebrates.  In  man  they  are  the  germs  which  i)roduce  malaria.  The 
malaria-producing  protozoans  spend  part  of  their  life  in  man  and  part  in  a 
certain  genus  of  mosquito  Anoph'eles).  When  this  mosquito  sucks  the 
blood  of  a  malarial  patient  the  germs  are  taken  into  the  stomach  of  the 
mosquito.  "  After  fertilization  the  oosphere  wanders  into  the  intestinal 
wall  of  the  mosquito,  grows  larger,  encysts,  and  produces  many  sporo- 
blasts,  which  in  time  form  many  sporozoites."  These  pass  out  with  the 
saliva  of  the  female  Anoph'eles  as  it  "  bites  "  another  person,  and  thus  the 
germs  of  malaria  are  transferred  to  his  blood,  where,  under  proper  condi- 
tions, they  multiply  rapidly,  and  fever  results.  It  is  evident  that  the  bite 
of  this  mosquito  does  not  cause  malaria  unless  the  mosquito  is  itself  in- 
fected with  the  germs. 

Yellow  fever  is  believed  to  be  caused  by  another  sporozoan  carried  by  a 
different  genus  of  mosquito  {Stegomy'ia).    (See  p.  157.) 


INFUSORIA 


CLASS   IV.     INFUSORIA 

The  fourth  class  of  protozoans  is  the  Infuso'ria,  of  which 
the  raramopchmi,  or  "sUpper  animalcule,"  is  a  type  (Fig.  2). 
1 1  is  somewhat  cyUndric  in  form  and  is  surrounded  by  a  cuticle 
perforated  with  minute  openings,  through 
which  the  protoplasm  projects  in  the  form 
of  short  hair-like  structures,  called  cilia, 
which  are  the  organs  of  locomotion. 
On  the  ventral  surface  of  the  Paramoecium 
is  a  groove  which  runs  backward  and 
inward  into  a  short  tube  or  gullet.  Both 
the  tube  and  the  gullet  are  lined  with 
vibrating  ciha  which  cause  currents  of 
water.  These  currents  carry  the  food  into 
the  inner  end  of  the  gullet,  where  it  is 
pushed  by  occasional  constrictions  into  the 
soft  endoplasm  and  carried  about  in  its 
movements  as  a  food  vacuole.  The  un- 
digested particles  are  cast  out  at  a  fixed 
point  in  the  cell  wall,  but  it  is  not  per- 
manently open,  so  it  is  not  easily  recog- 
nized. The  Paramoecium  is  supplied  with 
two  coiled  threads  which  may  be  used 
as  organs  of  defense.  The  Paramoecium 
has  two  nuclei,  one,  the  macronucleus, 
supposed  to  be  the  seat  of  all  vital  func- 
tions, and  the  other,  the  micronucleus, 
which  controls  the  reproduction.  The 
Paramoecium  reproduces  by  fission,  both 
nuclei  being  divided,  but  conjugation 
also  is  manifested.  In  conjugation, 
two  Paramoecia  unite  temporarily,  ex- 
change a  portion  of  the  micronuclei, 
and  perform  other  processes;  they  then 
separate,  and  continue  more  actively 
the  process  of  transverse  division  or 
fission. 

While  these  examples  are  only  a  few  of  the  thousands  of 
species  and  of  the  countless  myriads  of  individuals  of  proto- 
zoans, yet,  if  carefully  studied,  they  teach  many  things. 


Fig.  2. 
cixim  canddtiini, 
the  ventral  side,  sliow- 
ing  the  vestibule  en 
face;  arrows  inside  the 
body  indicate  the  di- 
rection of  protoi)lasinic 
currents;  thoseoutside, 
the  direction  of  water 
currents  caused  by  the 
ciha.  c.v,  Contractile 
vacuoles;/./',  food  vac- 
uoles; ir.r,  water  vacu- 
oles; ///,  inoutii;  tunc, 
macronucleus;  tnic,  mi- 
cronucleus; 6P,  esopha- 
gus; ;;,  vestibule.  The 
anterior  end  is  directed 
upward.  (Sedgwick 
and  Wilson.) 


BRANCH    PROTOZOA 


Fig.  3. — Organisms  very  abundantly  found  in  common  sea-water  that 
has  stood  a  few  days  in  an  open  shallow  dish:  a,  Acineta  with  embryo 
budding  off;  b,  resting  spores  of  alga,  with  bacteria;  c,  Chilodon;  d,  small 
Navicula;  c,  Cocconeis;  /,  larger  species  of  A^ovicula;  g,  heliozoan,  with 
two  entrapped  infusoria;  h,  germinating  alga  cells;  /,  small  colony  of  bac- 
teria in  zooglea  stage  with  small  flagellate  infusoria  near  by;  k,  flagellate 
infusorian;  m,  infusorian  Mesodinium;  n,  ciliate  infusorian;  v,  Vorticella, 
with  small  portion  of  its  stalk.     (Bull.  U.  S.  F.  C,  1895.) 


INFUSORIA  7 

Protoplasm. — Living  protoplasm  is  the  active  substance  of  all 
living  organisms.  All  the  forces  or  conditions  which  tend  to 
cause  response  or  reaction  in  living  protoplasm  are  called 
stimuli.  The  principal  stimuli^  may  be  classed  as  chemical 
stimuli,  differences  in  temperature,  light,  contact,  electricity, 
and  gravity.  Protozoans  possess:  (1)  Irritability,  that  property 
of  living  protoplasm  which  gives  it  power  to  respond  to  stimuli ; 
(2)  automatism,  the  power  of  movement,  or  of  changing  the  form. 

Locomotion. — Protozoans  move  by  means  of  pseudopodia, 
cilia,  or  flagella.  Some  forms,  as  the  Vorticel'la,  are  fixed,  and 
can  move  only  by  the  contractility  of  their  stalks  or  stems. 

Nutrition. — The  food  of  protozoans  is  composed  of  whatever 
minute  organisms  or  fragments  of  organic  matter  they  are 
able  to  obtain  in  the  water.  The  parasitic  forms,  of  course, 
simply  absorb  nutriment  from  the  liquids  of  the  host.  The  proc- 
ess of  nutrition  in  the  simplest  protozoan  consists  in  wrapping 
or,  more  correctly,  flov/ing  itself  about  the  particle  of  food, 
absorbing  the  nutriment  needed,  and  rejecting  what  it  cannot 
use.  Thus  we  see  that  it  has  the  power  of  selective  absorption, 
or  digestion. 

Circulation  is  brought  about  by  simply  changing  the  form  of 
the  body  mass,  thus  changing  the  position  of  the  absorbed 
nutriment  in  the  one-celled  body. 

Assimilation,  or  the  making  of  this  absorbed  material  into 
its  own  body  substance,  next  takes  place,  and,  as  a  consequence, 
growth.  The  using  up  of  assimilated  material  for  heat  or 
motion  (energy),  or  metabolism,  also  takes  place. 

1  The  reactions  (orientation)  of  animals  in  response  to  these  various 
stimuli  are  called  tropisms;  the  response  to  chemical  stimuli  is  called 
chemotropism;  to  heat,  ihcrniotropism;  to  light,  phototropism ;  to  contact, 
thigmotropism ;  to  electricity,  cUctrotropism;  to  gravity,  geotropistti,  and  so 
on.  Loeb  and  others  claim  tliat  the  movements  of  the  lower  forms  and 
many  of  those  of  the  higher  forms  are  purely  physical  and  chemical  reac- 
tions, just  exactly  as  those  known  to  us  in  the  inorganic  world.  H.  S. 
Jennings,  who  is  another  very  careful  investigator,  asserts  that  his  inves- 
tigations show  "  that  in  these  creatures  their  behavior  is  not,  as  a  rule,  on 
the  tropism  plan — a  set,  forced  method  of  reacting  to  each  particular  agent 
— but  takes  place  in  a  much  more  flexible,  less  dirtn'tly,  machine-like  way 
by  the  method  of  trial  and  error.  .  .  .  This  method  leads  upward,  offer- 
ing at  every  point  opportunity  for  development,  and  showing  even  in  the 
unicellular  organisms  what  must  be  considered  the  beginnings  of  intelli- 
gence and  of  many  other  qualities  found  in  higher  animals." 


8  BRANCH    PROTOZOA 

Respiration,  or  the  taking  in  of  oxygen  and  the  giving  off 
of  carbonic  acid  gas  and  other  wastes,  is  effected  by  the  al)sorb- 
tion  of  the  one  and  the  throwing  off  of  the  other  through  the 
surface. 

Excretion  takes  place  through  the  surface  or  through  the 
contractile  vacuole,  there  being  a  definite  point  at  which  the 
waste  is  ejected  in  the  more  advanced  forms,  such  as  the 
Paranurcimn  and  the  Vorticella. 

Multiplication. — While  these  life  processes  are  going  on,  the 
animal  grows  or  increases  in  size.  This  size  must  necessarily 
be  very  limited,  for  only  small  animals  could  live  in  this  ]>rimi- 
tive  way;  hence,  when  the  protozoan  has  reached  a  sufficient 
size,  it  divides  into  two  complete  halves,  each  half  containing 
its  share  of  the  original  cell-nucleus,  as  well  as  of  the  cytoplasm 
or  protoplasmic  cell  body.  This  cell  division,  or  the  multiplica- 
tion of  individuals,  is  called  fission.  After  simple  fission  has 
taken  place  for  many  generations  the  fusion  of  two  individuals, 
or  conjugation,  in  which  the  nucleus  of  one  individual  is  broken 
up  and  fused  with  that  of  the  other,  occurs.  After  this  fusion, 
the  process  of  fission  continues,  in  which  each  new  individual  now 
contains  a  portion  of  the  two  parent  nuclei  which  were  fused 
in  conjugation,  instead  of  one  parent  nucleus  as  before  con- 
jugation. This  surely  contains  a  suggestion  of  sexual  mul- 
tiplication, though  the  conjugating  cells  may  appear  exactly 
alike.  However,  instances  are  given  in  which  the  individuals 
differ  in  size,  the  "  males  "  being  smaller  and  more  mobile. 
Also  we  see,  not  exactly  "  alternation  of  generations,"  Init,  at 
any  rate,  alternation  of  methods  of  reproduction. 

Animal  Mind.^ — Of  the  mental  life  of  the  protozoan  little  is 
know^n.  If  the  rudiments  of  future  complex  animals  is  fore- 
shadowed in  the  protozoan,  why  may  we  not  recognize  the  fact 
that  here,  too,  is  found  the  merest  suggestion  of  the  mental  life 
as  well? 

It  has  been  abundantly  demonstratetl  that  protozoans  possess 
irritability  and  contractility.  It  has  been  shown  that  they  are 
sensitive  to  touch  or  contact,   and,   indeed,   can  discriminate 

1  Mind  is  here  used  in  the  biologic  sense,  and  is  the  "sum  total  of  all 
psychic  changes,  actions,  and  reactions." — Jordan  and  Kellogg's  "  Evolu- 
tion and  Animal  Life,"  p.  448. 


INFUSORIA  9 

between  a  hard  substance  and  a  softer  substance  suitable  for 
food,  as  well  as  to  recognize  their  kind  by  contact. 

Weir,  in  his  "  Dawn  of  Reason,"  tells  of  observations  with  an 
Adinoph'rys,  in  which  it  was  seen  to  discriminate  between  starch 
grains  and  uric-acid  crystals. 

Protozoans  are  also  known  to  be  responsive  to  heat  and  light. 
Weir  also  states  as  his  opinion  that  all  animals  can  distinguish 
day  from  night.  The  question  remains  as  to  whether  or  not 
this  is  ascertained  by  sight.  However  this  may  be,  there  can 
be  absolutely  no  vision,  because  there  is  no  mechanism  for  it. 

Importance  of  Protozoans. — (1)  They  furnish,  either  directly 
or  indirectly,  food  for  all  higher  forms  of  life.  (2)  They  are 
scavengers  of  decayed  organic  matter.  (3)  By  their  countless 
numbers  throughout  the  ages,  vast  formations  of  chalk  or  lime- 
stone have  been  made.  Myriads  of  them  are  still  sinking  to  the 
bottom  of  the  ocean  as  Glob'igeri'na  ooze  or  Radiolarian  ooze. 
Since  these  animals  are  aquatic,  geologists  know  that  wherever 
these  vast  formations  are  found,  there  was  once  the  sea.  (4) 
Some  of  them  are  parasitic  in  the  lower  animals  and  in  man, 
causing  diseases  which  are  ofttimes  widespread  and  serious.^ 

Classification. —  (Adapted  from  Parker  and  Haswell) : 

Clasfi.  Examples. 

I.  Rhizop'oda.  Amce'})a,  etc. 

II.  Mastigoph'ora.  Eugle'na,  Vol'vox. 

III.  Sporozo'a.  Gregarl'na,  etc. 

IV.  Infuso'ria.  Paramce'cium  and  Vorticel'la. 

1  Colonial  Protozoa.     See  Jordan's  "^Evolution  and  Animal  Life,"  p.  217. 


BRANCH  PORIFERA 

All  animals  except  the  Protozoans  are  multicellular  and  are 
classed  as  Metazoa. 

Differentiation. — In  all  we  find,  to  a  greater  or  less  degree, 
division  of  labor  among  the  cells,  or  the  differentiation  into  tissues 
and  organs  for  special  functions. 

Reproduction. — True  sexual  reproduction  is  the  characteristic 
m(>thod  among  Metazoans. 

Porifera. — These  aquatic,  many-celled  animals  were  formerly 
considered  as  plants.  Indeed,  they  look  like  seaweeds  among 
the  rocks  at  the  bottom  of  the  sea.  Most  of  the  sponges  are 
marine,  but  there  are  a  number  of  fresh-water  forms. 

Fresh-water  sponges  are  widely  distributed,  and  are  attached 
to  weeds  'or  submerged  objects  along  the  margins  of  clear 
springs  or  ponds. 

Sponges  vary  in  color  from  a  greenish  hue  to  red,  brown,  or 
flesh  color.  All  of  the  soft  parts,  as  well  as  the  skin  or  covering, 
is  gone  from  the  commercial  sponges. 

Their  shape,  as  is  seen  in  the  sponges  of  commerce,  is  irregu- 
lar even  in  the  same  species;  it  varies  with  the  environment,  in 
order  that  the  sponges  may  adapt  themselves  to  the  surface 
to  which  they  are  attached  or  the  depth  and  currents  of  the 
water.  Their  size  varies  from  a  fraction  of  an  inch  to  two  or 
three  feet  in  diameter. 

Structure. — The  body  of  the  Porifera  consists  of  many  cells 
arranged  in  two  layers,  an  inner,  or  endodenn,  and  an  outer,  or 
ectoderm.  There  is  a  middle  undifferentiated  layer  (mesoglea). 
The  simplest  sponge  is  cylindric  or  vase  shaped  (Fig.  4), 
while  others,  more  complicated,  consist  of  a  system  of  branch- 
ing tubes.  At  the  free  end  of  each  is  a  small  opening,  the 
osculum,  or  exhalant  orifice,  while  the  walls  of  the  cylinder  are 
perforated  by  exceedingly  minute  inhalant  pores.  The  ecto- 
derm consists  of  flattened  cells,  which  are  also  found  to  extend 
for  a  short  distance  inside  the  osculum,  while  the  rest  of  the  tube 

10 


MULTIPLICATION 


11 


is  lined  with  a  single  layer  of  peculiarly  shaped  columnar  cells, 
each  possessing  a  flagelluni. 

The  skeleton  is  developed  in  the  middle  layer  and  may 
consist  of  silicious  or  of  calcareous  spicules  of  a  great  variety  of 
form,  sometimes  they  are  anchor  shaiKul,, 
and  again  others  are  club  shaped,  sj^ear 
shaped,  or  cruciform.  The  so-called  glass 
sponges  sometimes  have  beautiful  silici- 
ous skeletons.  In  other  cases  the  skele- 
ton consists  simply  of  fine,  flexible,  inter- 
woven fibers  of  tough,  horny  spongin. 
It  is  the  skeleton,  denuded  of  the  flesh, 
or  sarcode,  that  covers  it  in  life,  which 
forms  the  commercial  sponge.  A  few 
sponges  have  no  skeletons. 

Nutrition. — There  are  no  organs  of 
digestion,  circulation,  or  respiration  in 
the  sponge.  The  food  consists  of  micro- 
scopic plants  or  animals,  or  of  minute 
particles  of  organic  matter  floating  in 
the  water.  The  food-laden  water  enters 
through  the  inhalant  pores  and  is  carried 
by  the  movement  of  the  flagella  through 
the  canals  or  paragastric  cavities.  The 
food  as  well  as  oxygen  is  taken  up  by 
the  cells  lining  the  canals  and  by  the 
ameboid  cells.  The  waste  is  carried  out 
by  the  outgoing  currents  of  water,  which 
empty  through  the  osculum,  or,  if  the 
sponge  is  complex,  the  oscula. 

Locomotion. — At  first  the  larval  sponge 
is  free  swimming,  by  means  of  cilia. 
It    soon    becomes    fixed   to   some    stone 

or  other  object  or  animal,  and  assumes  the  fixed  ways  of  its 
ancestors. 

Multiplication. — (1)  Asexual,  by  external  budcUng  and  the 
consequent  formation  of  a  united  colony,  or  by  internal  gem- 
mules;  (2)  sexual,  thus  insuring  the  perpetuation  of  the  species. 
Sponges  are  hermaphroditic,  that  is,  both  the  male  elements 


Fig.  4. — A  simple 
sponge  {Calcolynthus 
primigenius)  with  part 
of  outer  wall  cut  away. 
(After  Hackel.) 


12 


BRANCH    PORIFERA 


(sperm  cells)  and  the  female  elements  or  eggs  (ova)  are  con- 
tained in  the  same  individual  (Fig.  5).  It  is  from  the  union 
of  a  sperm  cell  with  an  ovum  that  the  new  individual  sponge 
is  developed.  The  sperm  cells  and  the  ova  rarely  mature  at 
the  same  time  in  the  same  individual.  Hence,  the  ova  in  the 
canals  of  one  sponge  are  fertilized  by  the  spermatozoa  of  an- 
other sponge,  which  are  carried  to  them  by  the  afferent  currents 
of  water  in  the  canals,  thus  insuring  cross-fertilization.  The 
eggs  are  retained  in  the  canals  until  the  blastula  stage  of  their 


Fig.  5. — First  stages  in  embryonic  development  of  the  pond  snail 
{Lymimas):  a,  Egg  cell;  h,  first  cleavage;  c,  second  cleavage;  d,  third  cleav- 
age; e,  after  numerous  cleavages  (Morula);  /,  blastula  (in  section);  g, 
gastrula  just  forming  (in  section);  h,  gastrula  completed  (in  section). 
(After  Rabl.)  This  may  be  taken  as  a  type  of  the  earliest  development  of 
all  many  celled  animals  (Metazoa).  (From  Jordan  and  Kellogg,  "  Animal 
Life,"  D.  Appleton  and  Co.,  Publishers.) 


development  is  reached,  then  they  are  set  free  and  pass 
out  at  the  exhalant  opening  or  osculum.  The  fresh-water 
sponges  (spongilla)  bear  small,  seed-like  bodies  called  gemmules 
toward  the  approach  of  winter.  The  parent  sponge  dies,  the 
gemmules  remain  dormant  until  the  next  spring,  when  the  rising 
temperature  calls  them  to  renewed  life.  They  grow  into 
mature  spongilla,  bear  other  gemmules,  and  thus  the  life- 
history  of  their  race  is  repeated. 

Animal  Mind. — Sponges   have   no   well-marked  nerve-cells, 
though  the  simplest  elements  of  both  nerve  and  muscle  have  been 


PROTECTIVE    RESEMBLANCE  13 

described  as  belonging  to  them.  It  is  evident  that  the  sponge 
possesses  irritability  and  contractility.  It  has  the  instincts  of 
self-preservation  and  of  the  perpetuation  of  its  species.  No  one 
can  correctly  interpret  the  psychologic  phenomena  of  any 
animal  until  he  has  passed  through  the  same  psychic  phenomena 
as  that  animal,  and  then  become  a  man  with  the  memory  of 
these  experiences  and  what  they  signified  to  that  animal.  Since 
we  cannot  do  that,  we  must  be  content  to  infer  the  significance 
of  certain  biologic  phenomena  from  comparison  with  our  own 
experiences. 

Environment. — As  has  been  said,   sponges  are  greatly  in- 
fluenced as  to  their  shape  by  the  objects  to  which  they  are  at- 


Fig.  6. — A  young  sponge.     (After  Burnet.) 

tached  and  by  the  depth  and  currents  of  the  water.  They  are 
much  more  nearly  uniform  in  deeper  waters.  The  plastic 
sponge  well  illustrates  the  influence  of  gravity  (geotropism) 
upon  an  animal.     It  also  shows  rheotropism} 

Protective  Resemblance. — Their  protective  resemblance  is 
exceedingly  good.  They  look  so  much  like  the  seaweed  and 
other  aquatic  vegetation  that  they  are  well  concealed  from 
the  animals  which  prey  upon  them,  such  as  worms,  crustaceans, 
mollusks,  and  other  marine  invertebrates.  Their  tough,  horny 
texture  and  their  silicious  or  calcareous  spicules  are  also  a 
means  of  protection.  Their  characteristic  odor,  said  to  re- 
semble garlic,  makes  them  distasteful  to  fishes. 
1  See  Glossary. 


14 


BRANCH    PORIFKKA 


Symbiosis. — Exam]:)les  of  symbiosis  are  found  among  them, 
as  that  of  the  sponge  and  the  crab.  The  sponge  attached  to  the 
cralj  is  carried  aljout  by  it  and  given  better  opportunity  of  ob- 
taining food  and  oxygen,  while  the  era)),  in  turn,  is  concealed 
from  its  enemies  by  the  sponge.  In  the  fresh-water  sponge,  a 
green  alga  sometimes  grows,  giving  the  green  color  to  the  mass. 

Various  small  marine  forms  are  found  in  the  sponges,  giving 
good  examples  of  commensalism.     Sponges  are  never  parasitic. 


Fig.  7. — Spongers  at  work.  The  "  sponge  hook  "  is  a  three-toothed 
curved  hook  attached  to  a  pole,  the  length  of  which  varies  with  the  depth 
of  the  water.  The  sponge-glass  is  a  common  water-pail  with  the  bottom 
knocked  out  and  a  pane  of  window  glass  put  in  its  place.  It  is  used  for 
seeing  below  the  surface  where  the  water  is  disturbed  by  ripples.  (Cobb, 
in  Circular  5.35,  U.  S.  F.  C,  1902.) 


Use. — They  are  of  use  as  food  for  other  animals,  and  their 
skeletons  form  a  very  useful  article  of  commerce. 

The  sponges  of  shallow  water  are  obtained  by  men  in  boats, 
with  a  dredge  or  a  long-handled  hook  or  rake  (Fig.  7) ;  those  of 
the  deeper  waters,  by  divers.  They  are  then  exposed  to  the 
air  for  a  time  and  then  heaped  up  in  water  again  in  tanks 


CLASSIFICATION 


15 


provided  for  them,  where  they  decay.  The  animal  matter 
in  them  is  "  beaten,  squeezed,  or  washed  out,"  and  their 
skeletons  sent  to  market  (Fig.  9). 

Geographic  Distribution, — Fresh-water  sponges  are  found 
in  streams  and  lakes  in  all  the  continents.  Marine  forms 
are  fountl  in  all  seas  and  in  all  depths,  from  the  shore  between 
tide-marks  to  the  deepest  abysses  of  the  ocean.  They  are  most 
abundant  in  tropical  waters. 

Geologic  Distribution. — Silicious  sponges  were  not  uncommon 
in  the  Cambrian  Period,  and  are  found  in  the  formations  from 


Fig.  8. — Bringing  sponges  from  the  vessels  to  spontic  wharf  at  Key  West. 
(Keport  V.  S.  F.  C,  1902.) 


that  time  on.  They  were  abundant  in  the  Jurassic  and  very 
abundant  in  the  Cretaceous  of  Europe;  none  have  been  found 
in  that  of  America. 

Important  Biologic  Facts. — Even  in  this  low  type  there  is  a 
differentiation  of  certain  cells  for  certain  purposes,  as  the 
skeletal  and  reproductive  cells.  True  sexual  reproduction  ap- 
pears for  the  first  time  in  the  Porifera.  Conjugation  was  noted 
in  the  Paramre'cium. 

Classification. — Sponges  are  of  three  kinds:  (1)  The  calcar- 
eous sponges,    containing   much    lime.     They  are  of    little  or 


16  BRA^X'H    PORIFERA 

no  commercial  value.  Example,  Grantia.  (2)  The  silicious 
sponges,  in  which  the  skeleton  is  largely  silica.  Example, 
Ewpledel'la.  (3)  The  horny  sponges  of  commerce.  Euspongia 
group.  To  this  group  belong  the  half-dozen  species  of  Florida 
and  the  Mediterranean  and  the  Red  Seas.  Our  American  sup- 
ply comes  principally  from  Florida  and  the  Mediterranean  Sea 


Fig.  9.— A  sponge  auction  at  Anclote.     (Report  U.  S.  F.  C,  1902). 

from  water  not  exceeding  30  fathoms  deep.  Examples  of  this 
group  are  Spongia,  and  the  fresh-water  forms  of  the  genus 
Syongilla. 

Most  zoologists  make  but  one  class  of  porifera;  others,  two 
classes : 

I.  Calca'rea. 

II.  Non-calca'rea. 


BRANCH  CCELENTERATA 

This  branch  comprises  our  fresh-water  Hydra,  and  a  few 
alHes,  and  the  marine  forms,  jelly-fishes,  corals,  and  sea-ane- 
mones. This  branch  finds  representatives  from  the  shore  line 
and  the  surface  to  the  profound  depths  of  the  ocean. 

The  body,  which  is  usually  radially  symmetric,  consists  es- 
sentially of  a  two-layered  sac,  which  is  open  at  one  end  and 
closed  at  the  other,  and  in  which  there  is  a  simple  or  branched 
gastric  cavity.  The  outer  layer  is  called  the  ectoderm;  the 
inner  layer,  the  endoderm,  and  a  gelatinous  non-cellular  layer 
between  them,  the  mesoglea.  Some  coelenterates  are  soft- 
bodied,  others  secrete  a  calcareous  or  limy  substance  called 
coral.  Around  the  free  open  end  of  the  sac-like  body  are  a 
varying  number  of  tentacles. 

Nettle  Cells. — Stinging  or  nettle  cells  are  characteristic  of 
this  branch,  except  in  Cetenoph'ora,  where  they  are  replaced 
by  adhesive  cells.  These  stinging  cells,  which  are  especially 
abundant  on  the  tentacles,  contain  a  fluid,  and  a  spirally  wound 
thread  provided  with  barbs,  which,  when  the  animal  is  disturbed, 
are  discharged  into  the  body  of  the  intruder,  paralyzing  it.  It 
is  then  seized  by  the  tentacles  and  drawn  into  the  mouth. 

Size. — Coelenterates  vary  in  size  from  the  little  fresh-water 
hydra,  a  fraction  of  an  inch  in  length  and  of  the  diameter  of  a 
pin,  to  the  giant  jelly-fishes,  as  the  Cya'nea,  which  sometimes 
reach  7  or  8  feet  in  diameter  and  have  tentacles  more  than  100 
feet  long. 

Locomotion. — Some  members  of  this  branch  are  free,  as  the 
jelly-fishes;  some  are  permanently  fixed;  as  the  Corals,  while 
some,  as  the  Hydras,  are  temporarily  fixed,  moving  from  one 
position  only  to  adhere  to  another,  and  thus  making  slow  pro- 
gression. 

Multiplication  is  both  sexual  (by  eggs)  and  asexual  (by 
budding) . 

Origin. — They  are  of  ancient  origin,  being  abundant  in  the 
Cambrian  Period. 


18 


BRANCH    CCELENTERATA 
CLASS  I.     HYDROZOA 


In  this  class  are  found  the  worldwide  fresh-water  Hydras  and 
the  marine  Hydroid  Colonies,  such  as  Campanula'ria  or  Obe'lia. 

The  Hydras  are  small  fresh-water  Hydrozo'a  from  ^  to  j  or 
possibly  h  inch  in  length.  They  may  be  white  or  colorless,  or 
green  or  brown. 

The  body  is  a  simple  cylinder  (Fig.  10)  or  sac,  closed  at  one 
end,  and  near  the  other  surrounded  by  six  or  eight  tentacles, 


Fig.  10. — Hydra:  Longitudinal  section  of  animal,  showing  m,  mouth; 
/,  tentacle;  d,  digestive  cavity;  b,  bud;  s,  spermary;  o,  ovary;  ec,  ectoderm; 
en,  endoderm.  Magnified.  (From  Dodge's  "  General  Zoology,"  American 
Book  Co.,  Publishers.) 

above  which  is  the  conical  hypostome,  at  the  apex  of  which  is  the 
mouth.  The  muscular  fibers  of  the  ectoderm  extend  lengthwise, 
while  those  of  the  endoderm  extend  around  the  body.^  If 
disturbed,  the  Hydras  protect  themselves  by  withdrawing  into 
a  tiny  sphere,  while  the  tentacles  contract  until  they  look  like 
so  many  small  buds.  The  endoderm  has  flagellate  cells  lining 
the  gastro vascular  cavity. 

1  Hertwig's  "  Manual  of  Zoology,"  Kingsley,  p.  230. 


HYDROZOA  19 

The  food  is  obtained  by  the  viscid  tentacles,  which,  when  the 
Hydra  is  undisturbed,  are  extended  (as  is  usually  the  body), 
ready  to  grasp  the  prey,  for  this  tiny  animal  is  carnivorous, 
feeding  upon  small  organisms,  usually  crustaceans.  There  are 
nettle  cells,  or  nematocysts,  in  the  ectoderm  of  the  tentacles. 
When  an  animal  comes  in  contact  with  a  tentacle,  the  nemato- 
cysts near  the  point  touched  throw  out  stinging  threads  which 
partially  paralyze  the  animal  by  the  fluid  which  they  discharge 
into  the  wound  they  have  pierced.  The  tentacles  then  pass 
the  prey  to  the  mouth,  which  opens  into  the  gastrovascular 
cavity,  in  which  digestion  is  carried  on  and  into  which  the 
wastes  are  gathered  and  thrown  out  through  the  only  opening, 
the  mouth.  The  Hydra,  by  its  wide-open  mouth  and  envelop- 
ing lips,  often  takes  in  organisms  much  larger  than  itself. 

Nerve-cells,  sex-cells,  and  nettle-cells  are  situated  in  the 
ectoderm. 

Multiplication  in  the  Hydra  is  both  sexual  and  asexual. 
It  reproduces  by  budding,  but  as  the  buds  mature  they  become 
detached,  so  that  no  permanent  colony  is  formed.  It  also 
reproduces  by  eggs,  the  animal  being  hermaphroditic,  that  is, 
the  reproductive  organs  of  both  sexes  are  found  in  the  same  indi- 
vidual. Near  the  base  of  the  tentacles  are  found  the  spermaries 
from  which  the  sperm  cells  are  discharged  into  the  water;  the 
ovaries  are  situated  farther  down,  near  the  lower  end  of  the 
body.  The  eggs  are  cross-fertilized,  that  is,  fertilized  by  the 
sperm  cells  of  another  individual.  After  fertilization  the  ova 
remain  in  the  ectoderm  for  some  time,  when  they  become  en- 
cysted in  spiny  cysts,  drop  off  into  the  water,  and  sink  to  the 
bottom.  They  lie  here  till  the  following  spring,  when  they 
break  their  casing  and  come  forth  as  minute  Hydras.  In  the 
encysted  condition  they  are  able  to  withstand  cold  and  drouth, 
thus  insuring  the  perpetuation  of  the  species.  Hydras  also  have 
the  power  of  regenerating  the  whole  body  from  a  part  in  case  of 
injury. 

Locomotion. — The  Hydra  is  temporarily  fixed  by  adhering 
to  the  submerged  stems  of  water  plants  by  means  of  a  sticky 
secretion  from  the  closed  end  of  the  tube.  It  can  detach  itself, 
and,  by  grasping  with  its  tentacles,  can  pull  itself  up  and  again 
attach  the  end  of  its  tubular  body  to  an  object.     By  this  cater- 


20 


BRANCH    CCELENTERATA 


pillar-like  looping  it  is  able  to  change  its  position  or  perform 
slight  locomotion. 

Dispersal. — While  the  mature  Hydra  has  very  limited  powers 
of  locomotion,  or  direct  dispersal,  its  offspring  may  be  widely 


Fig.  11. — A,  Part  of  the  colony  of  Bougainvil'lea  mus'cus,  one  of  the  com- 
pound Hydrozoa,  of  the  natural  size.  B,  Part  of  the  same  enlarged:  p,  A 
polypite  fully  expanded;  m,  an  incompletely  developed  reproductive  bud; 
m',  a  more  completely  developed  reproductive  bud;  /,  coenosarc  with  its 
investing  periderm  and  central  canal.  C,  A  free  reproductive  bud  or  medu- 
siform  gonophore  of  the  same:  7i,  Gonocalyx;  p,  manubrium;  c,  one  of  the 
radiating  gastrovascular  canals;  o,  ocellus;  v,  velum;  t,  tentacle.  (After 
Allman.) 


separated  from  the  parent  through  indirect  dispersal,  or  the 
drifting  about  of  the  encysted  eggs  by  means  of  currents  and 


HYDROZOA  21 

waves,  or  the  transporting,  by  the  same  means,  of  the  debris 
to  which  they  are  attached  in  later  hfe. 

Symbiosis  is  exempHfied  by  Hyd'ra  vir'idis,  or  the  green 
Hydra,  the  color  probably  being  due  to  the  presence  of  small 
green  algcB. 

Another  species  found  in  Russia,  Polijpo'dium  hydrifor'tne, 
of  which  little  is  known,  is  parasitic  on  sturgeon  eggs.^ 

A  Hydroid  Colony  (Fig.  11). — Suppose  a  hydra-like  animal 
to  bud  and  branch  until  it  looked  like  a  tiny  bushy  shrub.  This 
will  give  you  some  idea  of  these  plant-like  hydroids.  These 
hydra-like  animals,  or  polyps,  are  connected  by  a  system  of 
tubes,  the  common  stem  or  axis  bearing  many  individual  zooids. 


Fig.  12. — Ohe'lia  flabeUa'ta.     (Hincks.)       Fig.    13. — Obe'lia  comviissura'lis 


Obelia  (Figs.  12,  13)  is  a  good  representative  of  such  colonies. 
The  axis  is  made  up  of  a  creeping  horizontal  portion  and  of 
vertical  axes.  The  short,  alternate,  lateral  branches  of  these 
axes  bear  zooids  at  their  extremities,  or,  again  branching,  the 
polyps  or  zooids  are  borne  on  the  second  set  of  branches.  When 
these  zooids  are  immature,  they  are  little,  club-shaped  enlarge- 
ments. When  mature,  the  polyps  are  surrounded  proximally  by 
a  little  glassy,  protective  cup,  the  hydrotheca,  and  distally  bear 
about  a  score  of  tentacles.  These  are  the  nutritive  zooids, 
for  division  of  labor  is  found  here.  The  tentacle-bearing  indi- 
viduals procure  the  food,  and  since  the  tubes  are  all  hollow 

'  Herlwig's  "  Manual  of  Zoology,"  Kingsley,  p.  241. 


22  BRANCH    CCELENTERATA 

and  connected,  the  whole  colony  shares  the  food  thus  supplied. 
When  disturbed  the  polyp  withdraws  into  the  hydrotheca  for 
protection. 

Blastostyles. — But  while  the  majority  of  the  members  of  this 
colony  are  hydra-like,  tentacle-bearing  polyps  which  reproduce 
by  budding  only,  and  can  enlarge  the  original  colony,  they 
have  no  power  of  directly  producing  a  new  colony  in  a  more 
favorable  position.  There  is,  therefore,  another  set  of  individ- 
uals (see  Fig.  11).  These,  while  forming  a  part  of  this  tubular 
colony,  are  modified  in  their  form  for  a  particular  function. 
They  are  situated  toward  the  proximal  region  of  the  colony  and 
are  long,  cylindric  bodies,  known  as  blastostyles,  each  of  which  is 
enclosed  in  a  transparent  case,  the  gonotheca.  These  are  the 
reproductive  zooids,  and  bear  small  lateral  circular  buds  called 
medusa  buds,  which,  as  they  mature,  become  detached  and  pass 
out  through  an  opening  now  formed  at  the  end  of  the  gonotheca. 

Alternation  of  Generations. — These  medusa  buds  are  sexual 
and  dioecious,  i.  e.,  the  sexes  are  separate,  one  individual  producing 
the  ova  and  another  the  sperm  cells.  After  fertilization,  which 
takes  place  in  the  water,  the  egg  develops  into  a  simple,  free- 
swimming  ciliated  larva,  the  planula,  which  soon  attaches  itself 
to  some  object,  develops  into  a  polyp,  and,  by  budding,  forms 
a  new  colony.  This  regular  reproduction  by  budding,  and  then 
by  eggs,  and  then  by  budding  again  is  called  alternation  of  genera- 
tions, or  metagenesis. 

Medusae. — Careful  study  shows  that  the  Medusa  is  only  a 
highly  developed  or  modified  zooid.  The  cylindric  body  has 
been  developed  into  a  disk  or  umbrella-shaped  body  (Fig.  14) ; 
the  long  axis  has  been  greatly  shortened  and  is  suspended  be- 
neath the  center  of  the  sub-um])rella,  as  the  under  surface  of 
the  disk  is  called,  where  it  takes  the  name  of  mariubrium,  or 
"  handle."  At  the  free  end  of  this  manubrium  is  the  mouth, 
which  opens  into  the  gastric  cavity  that  occupies  the  whole 
interior  of  the  handle. 

At  the  base  of  the  manubrium  four  radial  canals,  equally 
distant  from  each  other,  are  sent  out  to  the  circular  canal, 
which  runs  around  the  margin  of  the  umbrella,  but  within  its 
substance.  Thus,  the  food  taken  into  the  mouth  is  distributed 
to  the  whole  animal.     The  whole  canal  system  is  lined  by  endo- 


HYDKOZOA 


23 


derm,  which  is  ciliated.  The  endoderm  also  forms  the  axes 
of  the  tentacles.  There  is  also  a  layer  of  endoderm  between  the 
radial  canals  extending  from  the  circular  canal  to  the  gastric 
cavity.  Between  the  endoderm  and  the  ectoderm,  which 
covers  the  convex  surface  or  ex-umbrella,  is  a  much-thickened 
jelly-like  mass  of  the  mesoglea,  while  between  the  endoderm 
and  the  ectoderm  covering  the  sulj-uml^rella  there  is  a  thin 
layer  of  mesoglea.  The  ectoderm,  of  course,  covers  the  tenta- 
cles, where  it  is  well  supplied  with  stinging  cells.  At  the  margin 
the  ectoderm  of  both  the  sub-  and  ex-umbrellas  forms  a  narrow 


1  2 

Fig.  14. — 1,  Pela'gia  panopy'ra,  oral  view  of  mature  medusa.     2.  The  same, 
side  view.     (Mayer,  in  Bull.  U.  S.  F.  C,  1903.) 

fold  or  shelf,  the  velum,  which  hangs  down  when  at  rest,  but 
draws  up  like  a  diaphragm  across  the  bottom  of  the  umbrella 
when  the  bell  contracts.  By  the  forcing  out  of  the  water  the 
animal  is  forced  forward,  and  so  locomotion  is  effected.  Around 
the  outside  of  the  velum  is  a  row  of  tentacles,  usually  four  or 
some  multiple  of  four  in  number. 

Muscles  of  a  longitudinal  character  control  the  tentacles, 
while  circular  striped  muscles  surround  the  sub-umbrella  and 
velum,  and,  by  contracting  the  umbrella  and  velum,  produce 
locomotion. 


24 


BRANCH    CCELENTERATA 


The  nerve  ring  surrounds  the  margin  between  the  circular 
muscles  of  the  umbrella  and  those  of  the  velum.  At  the  bases 
of  two  of  the  tentacles  of  each  quadrant  there  are  sense  organs. 
They  probably  aid  the  medusa  in  determining  in  what  direction, 
with  regard  to  the  vertical,  it  is  swimming,  that  is,  whether  it  is 
moving  up,  down,  or  sidewise.  In  other  medusae  the  simplest 
of  eyes,  red  pigment  spots,  which  may  or  may  not  have  a  lens, 
are  found. 

The  food  of  the  medusa  consists  of  both  plants  and  animals. 
It  is  very  voracious  and  grows  rapidly  after  leaving  the  colony. 


Nutritive  individual;  b,  reproduc- 
(Bull.  455,  U.  S. 


c.  a- 

Fig.    15. —  Hydractin'ia  polydi'na 
tive  individual;  c,  spiral  zooids  or  fighting  individuals. 

F.  C.) 

Multiplication.— After  a  time  either  eggs  or  sperm  cells 
develop,  and  are  set  free  in  the  water,  where  they  unite  with 
those  of  some  other  medusa  and  develop  into  the  tiny  larval 
form,  which  soon  attaches  itself  and  grows  into  a  hydroid,  to 
bud  and  ])ranch  and  produce  again  the  medusse,  thus  repeating 
the  life-cycle  and  the  reproduction  by  alternation  of  genera- 
tions. 

There  are  more  than  a  thousand  species  of  the  class  Hydrozoa.  In 
some  forms  (Fig.  15),  as  the  Hy'dractin'ia,  there  are  several  classes  of 
individuals— the   nutritive,    the   defensive,    and    the   reproductive— with 


HYDHOZOA 


the  corresponding  division  of  labor.  These  Ilijdractin'la  li\e  uyion  the 
surface  of  the  shells  of  sea-snails  or  whelks,  which  are  inhabited  by  hermit 
crabs,  and  afford  another  good  example 
of  symbiosis.  The  Hydractinia  gets 
free  transport  a  I  ion,  aiding  it  in  secur- 
ing food;  it  also  proba])ly  feeds  upon 
minute  fragments  of  the  crab's  food; 
while  the  crab,  in  turn,  is  protected 
from  intruders  by  the  stinging  cells  of 
the  Hi/drdiiiniii.  If  the  hydroids  are 
in  any  way  lorn  from  the  shell,  the  crab 
finds  anotlicr  colony,  and,  tearing  it 
loose  from  its  supporting  object,  places 
it  upon  its  borrowed  shell. 

Millcp'ora  alcicor'nia  is  a  species  of 
so-called  hydroid  "corals" — the  beau- 
tiful elk-horn  or  stag-horn  coral  of 
Florida.  The  permanent  colony  num- 
bers thousands  of  individuals,  which 
differ  in  their  structure  according  to 
their  division  of  labor.  Their  cal- 
careous skeletons  are  a  cuticular  prod- 
uct of  the  ectoderm. 


Another  order  of  the  class  of 
Hydrozoa  is  characterized  by  a 
closed  float  containing  air  or  gas 
which  serves  to  keep  the  colony 
vertical  in  the  water.  In  the 
"  Portuguese  man-of-war  "  (Fig. 
16),  found  as  far  north  as  New 
England,  there  are  suspended 
from  the  large  float  (3  to  12  cm.)^ 
peacock  blue,  or,  in  some  cases, 
orange  in  color,  several  kinds  of 
individuals;  some  of  them,  many 
feet  in  length  and  armed  with 
nettle  cells,  capture  the  food  and 
bear  it  to  the  mouth-bearing  or 
nutritive  polyps,  which  digest  the 
food  and  distribute  it  to  the  col- 
ony. Others,  the  feelers,  are  groups  of  deep  blue  medusoids  re- 
sembling bunches  of  grapes,  while  others,  with  swimming  move- 
ments, aided  by  the  wind,  drive  the  colony  from  place  to  place 


Fig.  16. — A  Portuguese  man- 
of-war  {Fhysalia),  with  man-of- 
war  fishes  ( Nomeus  gronovii)  liv- 
ing in  the  shelter  of  the  stinging 
feelers.  Specimens  from  off 
Tampa,  Fla.  (From  Jordan  and 
Kellogg,  "  Animal  Life,"  D. 
Appleton  and  Co.,  Publishers.) 


^  Parker  and  Has  well. 


26  BRANCH  ccelentp;rata 

CLASS   II.     THE   SCYPHOZO'A 

Jelly-fishes  are  soft  umbrella-like  creatures  resembling  molds 
of  jelly  or  gelatin,  as  one  sees  who  picks  them  up  along  the  beach, 
where  they  have  been  cast  ashore  by  the  waves.  Their  tissues 
are  very  watery,  hence  the  scarcity  of  their  fossil  remains. 
However,  very  perfect  impressions  of  jelly-fishes  are  found  in 
the  upper  Jurassic  Period.  Most  jelly-fishes  are  marine  and 
free  swimming,  though  a  few  are  temporarily  attached.  They 
are  most  abundant  in  the  tropics.  Great  schools  of  them  are 
sometimes  seen.  Sometimes  they  are  phosphorescent.  They 
vary  in  size  from  about  4  mm.,  in  the  simple  little,  bell-like 
Tessera,  to  1  foot  in  the  Aurelia,  and  7  or  8  feet  in  diameter  in 
the  Cyanea,  whose  tentacles  sometimes  reach  the  length  of 
130  feet.  A  small  form,  Gonionemus,  found  at  Wood's  HoU, 
Mass.,  is  green  and  about  1  inch  in  diameter.  It  grows  on  eel- 
grass.  All  are  carnivorous,  feeding  mostly  upon  crustaceans, 
though  some  of  the  larger  ones  capture  fishes  of  considerable  size. 

The  food  is  captured  by  the  tentacles,  which  are  suspended 
from  the  margin  of  the  umbrella  and  which  are  armed  with 
stinging  thread  cells. 

Locomotion  is  effected  by  the  flapping  of  the  umbrella-like 
body,  there  being  usually  no  velum. 

Minute  colored  "  eye-specks  "  are  around  the  rim. 

Multiplication  usually  is  by  alternation  of  generations,  but 
the  young  medusa  or  ephyra,  as  it  is  called,  undergoes  a  meta- 
morphosis or  change  of  form  as  it  matures.  In  some  cases  the 
egg  develops  directly  into  the  larval  medusa  and  there  is  no 
alternation  of  generations,  but  simple  metamorphosis. 

CLASS  m.     ACTINOZO'A 

This  class  includes  sea-anemones,  sea-pens,  and  corals. 
Only  the  polyp  form  is  found  in  this  class,  no  medusa  being 
known  among  them.  They  are  exclusively  marine.  They  are 
usually  fixed  and  many  form  permanent  colonies. 

One  point  in  their  development  is  a  step  in  advance  of  the 
Hydrozoa,  i.  e.,  the  development  of  a  gullet,  esophagus,  or 
stomodceum,  the  beginning  of  which  is  seen  in  the  Scyphozoa. 
The  hypostome,  which  in  Hydrozoa  bore  the  mouth  at  its  apex, 


ACTINOZOA 


27 


is  here  inflected  and  forms  a  tube  dipping  down  into  the  body 
cavity,  but  not  reaching  the  Ijottom  of  it.  The  lower  end  of  this 
tube  or  esophagus  (which  is  really  the  beginning  of  the  ali- 
mentary tube  of  higher  animals)  corresponds  to  the  mouth  of 
the  Hydra,  so  that  the  tube  is  lined  with  ectoderm.  The  mouth 
is  the  only  external  organ,  and  serves  both  for  the  entrance  of 
food  and  the  ejection  of  waste.  The  body  cavity  about  this 
tube  is  divided  by  thin  partitions  into  radiating  spaces. 

No  actinozoan  is  microscopic.  All  are  long  lived.  One  in  an 
English  aquarium  lived  more  than  sixty  years. ^  The  sea-ane- 
mones and  all  true  corals  producing  reefs  and  islands  have  the 
number  of  their  tentacles  in  multiples  of  six. 


,-*«^ 


f.; 


Fig.  17. — Sea-anemone  {Metrid'ium).     (Emerton.) 


The  Sea-anemones  (Fig.  17). — As  one  gazes  in  wonder  at 
the  sea-anemones  in  their  marine  home,  he  can  scarcely  persuade 
himself  that  those  beautifully  colored  objects,  so  flower-like — 
hollow  cups  with  their  petals  and  sepals  of  such  wonderful  tints 
— are  else  than  flowers.  But  he  touches  one,  the  "  sepals  and 
petals  "  close  in  upon  his  fingers,  they  tingle,  and  he  finds  that 
this  flower-like  object  is  an  animal  and  that  the  "  sepals  and 
petals  "  are  tentacles.  A  very  different  appearance  it  makes 
when  the  body  has  been  drawn  down  close  to  its  attachment  by 
the  longitudinal  muscles,  while  the  circular  muscles  shut  in  the 
1"  General  Zoology,"  Dodge,  p.  75. 


28 


BRANCH    CCELEXTERATA 


Fig.  18. — Athc'lla  iiiirdh'iUs.     Ciencral  view  of  branch.     View  of  a  calice. 
(Vaughan,  in  Bull.  U.  S.  F.  C,  1900.) 


Fig.    19. — Favia  fragum    (Esper).     View   of   a   corallum   from    the   side. 
(Vaughan,  in  Bull.  U.  S.  F.  C,  1900. j 


retracted  tentacles  until  it  looks  like  a  round  mass  of  flesh.     The 
tentacles  are  hollow  and  are  armed  with  lasso  cells,  which  are 


ACTINOZOA  29 

useful  not  only  for  defense,  but  for  capturing  crabs  and  small 
fishes  which  form  the  anemone's  food. 

Sea-anemones  are  solitary,  that  is,  they  form  no  permanent 
colony.  They  have  no  true  skeleton.  There  is  no  alternation 
of  generations.  They  vary  in  size  from  |  inch  to  2  feet  in 
diameter,  and,  though  attached,  have  the  power  of  changing 
their  position. 

The  Stony  Corals  (Fig.  18). — The  coral  polyps  resemble  small 
sea-anemones  on  a  much-branched  stem.     The  calcareous  skele- 


Fig.  20. — Isopo'ra  murica'ta  forma  prolif'era  lam.      End  of  branch,  height 
9  cm.     (Vaughan,  U.  S.  F.  C.  Bull.,  1900.) 


ton  is  secreted  by  the  ectoderm.  The  branched  form  arises 
from  the  continual  l)udding  and  branching  from  a  parent  stem. 
The  different  forms  (Fig.  19)  of  coral  are  caused  by  the  different 
modes  of  budding  in  the  various  species.  Corals  are  of  various 
colors  and  some  are  said  to  be  phosphorescent. 

The  members  of  a  coral  colony  are  organically  connected. 
Each  feeds  himself,  it  is  true,  but  no  individual  of  the  colony  is 
independent  of  the  others. 

The  size  varies  from  that  of  the  head  of  a  pin  to  ^  inch, 


30 


BRANCH    CCELENTKKATA 


the  solitary  mushroom  coral  being  sometimes  of  the  exceptional 
size  of  1  foot  in  diameter. 

These  myriads  of  coral  polyps  (Fig.  20)  secrete  great  quanti- 
ties of  lime,  the  waves  break  off  the  branches,  grind  them  up, 
mix  them  with  sand  and  shells,  and  thus  build  up  coral  reefs 
and  islands  of  vast  extent.     These  are  confined  to  warm  regions 


Fig.  21. — A  sea-fan. 


about  30  degrees  on  each  side  of  the  equator,  since  coral  colonies 
cannot  live  in  temperature  below  60°  F.,  and  for  a  full  luxuriance 
a  higher  temperature  is  necessary.^  They  are  also  shallow  water 
animals,  living  from  the  high-water-mark  to  a  depth  of  not 
more  than  20  fathoms.  They  must  also  have  salt  water,  hence 
they  cannot  live  at  the  mouth  of  a  river. 

^Scott's  "Geology." 


CTENOPHORA 


31 


The  Odocoral'la,  or  those  forms  which  have  eight  tentacles,  are  found 
in  all  seas,  both  in  shallow  water  and  at  great  dejjths.  They  inchule 
the  organ-pipe  coral,  the  precious  red  coral  {('(imllium  rubniin)  of  the  Medi- 
terranean Sea,  and  the  sca-jx'iis  and  the  sea-fans.  The  mesoglea  of  many 
octocoralla  contains  irri'^;iilar  calcareous  spicules. 

The  sea-pens  {Pvini(ili(l(i'nin  usually  form  an  elongated  colony.  The 
stem,  one  end  of  which  is  embedded  in  the  sand  or  mud  of  the  sea  bottom, 
is  supported  by  a  calcareous  or  horny  skeleton.  The  distal  portion  is  dis- 
tended like  a  feather  and  bears  the  dimorphic  polyps. 


Fig.  22. — Photograph  taken  with  the  camera  submerged,  to  show 
aquatic  animals  in  their  natural  environment.  In  the  background  are  seen 
sea-fan  and  branching  gorgonian.     (Bull.  U.  S.  B.  F.,  1907.) 

The  sea-fans  (Gorgona'cea)  (Fig.  21)  have  a  branched  colonial  axis  formed 
of  horny  or  calcareous  substance  from  the  ectpderm,  with  spicules  in  the 
mesoglea. 

In  some  cases  the  skeleton  formed  by  the  spicules  forms  a  branched 
axis,  as  in  Corallium  ruhrum,  or  it  may  form  a  "  series  of  connected  tubes 
for  the  individual,  as  in  the  organ-pipe  coral  {Tubip'ora}."  "  The  red  coral 
is  fovmd  only  in  the  Mediterranean  Sea  at  a  depth  of  from  10  to  20  fathoms. "^ 


CLASS   IV.     CTENOPHORA 

The  Ctenoph'ora,  or  "  comb-jellies,"  are  so-called  from 
eight  bands  of  comb-like  cilia  fused  at  their  bases,  which  sur- 
round their  nearly  transparent  bodies.     The  body  is  non-con- 

^  Parker  and  Haswell'.'*  "Zoology." 


32  BRANCH    CCELENTERATA 

tractile,  and  these  cilia  accomplish  locomotion.  They  are 
free  and  single,  there  being  no  polyp  stage.  They  are  found 
from  the  tropical  to  the  arctic  seas.  They  are  small — from 
5  to  20  mm.- in  diameter — and  their  shape  varies  from  that  of  a 
pear  to  a  sac-like  or  ribbon-like  form.  They  have  but  two 
tentacles.     They  are  hermaphroditic,  multiplying  by  eggs. 

The  central  nervous  system  is  represented  by  a  ciliated  area 
on  the  aboral  pole,  and  is  connected  with  a  single  sensory 
organ. 

Economic  Value. — The  animals  of  this  branch  are  of  great 
use  to  man,  indirectly,  by  furnishing  food  for  other  animals,  and, 
directly,  by  the  formation  of  great  beds  of  limestone  and  of 
coral  reefs  and  islands,  also  by  forming  an  article  of  commerce 
of  no  small  value.  ^ 

"  The  red  coral  of  commerce  is  obtained  in  the  Mediterranean 
Sea  off  the  coast  of  Africa.and  the  west  coast  of  Italy.  The  price 
varies  according  to  the  color.  The  finest  rose  pink  in  large 
pieces  is  valued  at  $400  or  more  an  ounce.  The  common 
article  brings  from  $1  to  $1.50  an  ounce. "^ 

Geologic  Distribution. — The  hydrozoa  are  believed  to  be 
represented  by  the  Graptolites,  which  appeared  in  the  Cambrian 
Period,  were  numerous  in  the  Ordovician,  greatly  diminished  in 
the  Silurian,  and  almost  extinct  in  the  Devonian.  Large 
numbers  of  casts  of  jelly-fishes  are  found  in  the  Cambrian  rocks.^ 
Hydroids  and  true  corals  were  important.  Marine  life  and  reefs 
were  formed  in  the  Silurian  Period.  Corals  vastly  increased 
in  size  and  numl)er  in  the  Devonian  Period,  and  were  abundant 
in  the  Carboniferous,  contributing  largely  to  the  limestone. 
Hydractinia  were  found  in  the  Cretaceous  Period. 

Important  Biologic  Facts. — In  the  Ctenophora  is  found  for  the 
first  time  a  true  middle  layer  of  mesoderm  cells.'* 

In  the  hydroid  colony  is  found  the  division  of  labor  among 
the  different  sets  of  individual  zooids  and  a  differentiation  of 
structure  according  to  their  function. 

1  "  The  fishing  for  the  red  coral  (Corallium  ruhrum)  at  Naples  amounts 
yearly  to  half  a  million  dollars." — Kingsley. 
2 Adam's  "Commercial  Geography." 
3  Scott's  "Geology,"  p.  371. 
^Parker  and  Haswell's  "Zoology,"  vol.  i,  p.  207. 


CTENOPHORA 


Classification. — 

Class. 
I.  Hydrozo'a. 
II.  Scyphozo'a. 

III.  Actinozo'a. 

IV.  Ctenoph'ora. 
3 


33 


Examples. 
Hy'dra,  Hydroid  Colonies. 
Jelly-fishes. 

Sea  Anemones  and  Coral  Polyps. 
"Comb-jellies." 


BRANCH  PLATYHELMINTHES 

Platyhelmin'thes,  or  Flat  Worms,  have  three  germ  layers, 
the  ectoderm,  the  mesoderm,  and  the  endoderm.  They  are 
flattened  dorsoventrally  and  are  bilaterally  symmetric.  They 
have  no  skeleton,  no  circulatory  system,  and  no  coelom  or  body 
cavity.  They  have  an  anterior  and  a  posterior  end,  but  rarely  a 
distinct  head. 

The  nervous  system  is  composed  of  superesophageal  ganglia 
and  lateral  nerve-trunks. 

The  excretory  system  consists  of  water-vascular  tubes. 
There  is  no  anal  opening. 

Development  is  sometimes  with  and  sometimes  without  a 
metamorphosis. 

Habitat. — Some,  as  the  liver-fluke  and  the  tapeworm,  are 
parasitic;  others,  as  Planaria,  live  in  fresh  water.  Some  live 
in  moist  places  or  in  the  mud  at  the  bottom  of  ponds  and 
streams;  while  others,  as  Leptoplana,  are  marine. 

Size. — The  parasitic  forms  are  sometimes  30  or  40  feet  in 
length,  while  the  free  forms  are  but  2  or  3  inches  in  length. 
These  are  often  found  under  stones,  and  are  exceedingly  deli- 
cate. 

Protective  resemblance  is  very  great  in  some  species,  while  a 
few  are  nearly  transparent. 

CLASS  I.  TURBELLARIA 
The  class  Turbella'ria  consists  principally  of  non-parasitic 
forms  which  are  ciliated  externally.  There  is  usually  a  diges- 
tive cavity.  The  prevailing  shape  is  leaf-form,  like  that  of 
Plana' ria.  Some  marine  forms,  however,  are  shaped  like  "  a 
thin  ribbon  with  puckered  edges,"  others  may  be  thickened  and 
band-like,  as  in  the  land  planarians,  while  others  approach  the 
shape  of  a  cylinder.  Locomotion  is  performed  by  the  fine 
vibratile  cilia  which  cover  the  surface.  The  ectoderm  contains 
sensory  and  gland-cells. 

34 


TREMATODA 


35 


CLASS   II.     TREMATODA 

The  class  Tremato'da  is  comprised  of  worms  either  internally 

or  externally  parasitic.     The  body  is  usually  thicker  than  that 

^  of    the     turbellarians.       The 

form     is     usually      leaf-like, 


■-y  ?;  W 


Y\fr.  2'A. — 'I1ic  common  livor-Huke 
(^V^s■^/'(;/(/ //,7«;/'/r,/ )  enlarged  toshow 
theaiiatomic  <'liaract('r.s:  ac,  Aeetab- 
uluni ;  c,  />.,  cirrus  ])<)uch;  I,  intestinal 
ceca;  >/i,  mouth  with  oral  sucker;  ov, 
ovary;  p.  b.,  pharyngeal  bulb;  s.  g., 
shell  gland;  t,  profusely  branched 
testicles;  ut,  uterus;  va,  vagina; 
V.  g.,  profusely  branched  vitcllogene 
gland.     (After  Stiles,  1894,  p.  300.) 


though  it  is  sometimes  elon- 
gated. The  anterior  end  is 
distinguished  by  the  arrange- 
ment of  suckers,  and,  in  some 
of  the  external  parasites,  by 
eyes. 


Fig. 
mon 

boring  into  a  snail — x  370. 
Thomas,  1883,  p.  285.) 


The  suckers  are  organs  of  adhesion  and  are  sometimes  armed 
with  })ristles  or  hooks.  They  are  also  used  in  locomotion,  which 
is  a  sort  of  looping,  like  that  of  the  leech.  Except  in  two  cases 
the  vibratile  cilia  are  not  found  on  the  surface. 


36 


BRANCH    PLATYHELMIN'THES 


The  trematodes  are  hermaphroditic,  and  the  development  may 
be  either  with  or  without  a  metamorphosis. 

The  Liver-fluke  (Fig.  23)  is  parasitic  in  sheep.  The  eggs  pass  down  the 
bile-ducts  of  the  sheep  into  the  intestine,  and  from  there  to  the  exterior, 
when  the  embryo  escapes  by  the  separating  of  the  Hd,  or  operculum,  from 
the  egg-shell. 

The  ciliated  larva  swims  about  in  the  water 
or  remains  in  the  damp  vegetation  until  it 
comes  in  contact  with  a  pond  or  land  snail 
(Fig.  24).  It  then  bores  into  the  body  of  the 
snail,  where  it  develops  into  a  spurocy.st 
(Fig.  25),  which  produces  redice.  These  rciliir 
possess  a  mouth,  a  pharynx,  an  intcj^tim",  and 
an  opening  for  the  escape  of  the  young,  which 
are  internally  produced.  According  to  the 
season,  these  young  are  cercaricc  or  rediw, 
several  generations  of  which  may  follow 
before  the  cercaricp  appear.  The  cercarice  are 
adapted  for  aquatic  life. 


Fig.  26. — Free-swimming  cercaria 
of  the  common  liver-fluke,  greatly 
enlarged.     (After  Leuckart.) 


Fig.  25. — Sporocyst  of  the  com- 
mon liver-fluke  from  the  body  of  a 
snail,  containing  redise  in  course  of 
dev(>lopnicnt — enlarged  200  times. 
(After  Leuckart.) 

The  cercaria:  (Fig.  26)  escape  from  the  snail,  swim  about  with  their  vibra- 
tile  tails  for  a  time,  when  the  tails  drop  ofT  and  the  cercaricp  become  encysted 
on  a  plant.  When  this  plant  is  eaten  by  a  sheep,  cow,  or  hog,  the  young 
escapes  from  the  cyst  and  makes  its  way  up  the  bile-ducts  to  the  liver, 
where  it  develops  into  the  mature  worm  and  produces  reproductive  organs, 
thus  completing  the  life-cycle. 

Sheep  pa.stured  in  swampy  places  are  likely  to  be  infected  by  this  para- 
site, and  wet  seasons  cause  epidemics. 


CESTODA 


37 


In  England  the  annual  loss  of  shc<'i)  ki 
at  $1,000,000,  and  it  has  been  known 
There  have  been  a  few  cases  of  this  paia 


d  hv  the  liv(>r-flukes  is  estimated 
reach  -So, 000,000  in  one  year. 
c  found  in  num. 


CLASS   III.     CESTODA 

A  tapeworm  {Tce'nia  so'Kum)  is  a  parasite  in  the  intestine 
of  man.  It  is  ribbon  shaped  (Fig.  27),  being  much  narrower  at 
the  attached  end,  the  head,  or  scolex. 

The  scolex  is  knob-shaped  and  bears  the  organs  of  attacli- 
ment,  a  circle  of  hooks  at  the  end,  and  a  sucking  disk  or  cup- 
shaped  sucker  on  each  of  the  four  sides.  The  attachment  is 
temporary. 


,g^ll1H|iiiiiJjjjiimTrnniiJjiriTi 


Ta'nin  sagina'ta.     (Eichhorst.) 


Segments. — The  remainder  of  the  tapeworm,  except  a  short 
portion  immediately  posterior  to  the  head,  is  made  up  of  a  series 
of  segments  or  proglottides,  the  number  of  which  varies  in  differ- 
ent species.  In  Taenia  solium  there  are  about  eight  hundred  and 
fifty  segments,  while  in  the  smaller  species  there  are  three  or  four 
hundred,  and  in  the  larger  species,  several  thousand.  These 
segments  or  proglottides  are  derived  from  the  head  by  a  kind 
of  budding.  Thus  it  is  that  so  long  as  the  head  remains  the 
tapeworm  continues  to  grow. 

Digestion. — There  is  no  digestive  system,  the  nutrition 
simply  being  absorbed  from  the  liquids  of  the  host. 

The  nervous  system  consists  of  a  pair  of  ganglia,  from  which 
two  main  nerve-cords  extend  l)ack  through  the  length  of  the 
worm. 

The  excretory  or  water-vascular  system  consists  usually  of 


38 


BRANCH    PLATYHELMINTHES 


four   principal   trunks   extending   throughout   the   scolex   and 
proglottides. 

Multiplication  and  Development. — Each  proglottis,  as  it 
matures,  becomes  hermaphroditic.  Since  these  proglottides 
are  originally  tleveloped  from  the  head,  the  posterior  ones  are 
oldest.  When  filled  with  embryos,  they  are  detached  and  pass 
out  with  the  waste  material  from  the  intestine.  When  taken 
into  the  alimentary  canal  of  the  hog  with  its  food,  the  hooked 
embryos  bore  through  the  intestinal  wall  and  into  the  voluntary 
muscles,  where  they  grow  and 
continue   to   develop  until   they 


Fig.    28 — Tcenia   echinococ^cus,  en-  Fig.  29. — Portion  of  the  intestine 

larged.     (Mosler  and  Peiper.)  of  a  dog  infested  with  echinococcus 

tapeworms,    natural   size.      (Oster- 
tag.) 

reach  the  bladder-worm  stage,  or  cysticercus.  When  pork 
containing  a  cysticercus  is  eaten,  unless  it  has  been  killed  by 
thorough  cooking,  the  head  is  everted  from  the  bladder-like 
covering  and  is  attached  to  the  intestinal  wall  of  the  host, 
where  proglottides  are  rapidly  developed.  These  mature  in 
ten  or  twelve  weeks. 

Species. — There  are  many  species  of  tapeworms.  One  form, 
Tcenia  saginata,  which  occurs  in  man,  is  obtained  through 
eating  beef  cooked  rare;  another  form,  Tcenia  solium,^  already 
mentioned,   from   eating  pork;  and  another,    Bothrioceph'alus 

1  Tcenia  solium  is  sometimes  found  in  the  encysted  or  intermediate  stage 
in  the  muscles,  eye,  or  brain  of  man.  The  eggs  are  thought  to  have  been 
taken  into  the  stomach  with  lettuce,  cress,  and  the  like,  which  had  been 
watered  with  liquid  manure. 


NEMERTINEA  6\) 

latus,  from  eating  fish.  The  latter  species  is  the  largest  tape- 
worm found  in  man  and  sometimes  reaches  a  length  of  40  feet, 
and  is  composed  of  more  than  four  thousand  proglottides.  It 
is  rare  in  America,  but  is  abundant  in  Russia,  Switzerland,  and 
the  eastern  provinces  of  Prussia.  Another  form  (Fig.  28), 
perhaps  the  most  formidable,  is  a  small  one,  Toe'yiia  echinococ'cus, 
which  lives,  in  the  adult  stage,  in  dogs  (Fig.  29),  and  the  eggs 
are  easily  taken  into  the  human  stomach  by  a  person  fondling 
and  kissing  infested  dogs.     The  embryos  (Fig.  30),  when  set 


Fig.  .30. — Portion  of  hog's  liver  infested  with  echinococcus  bladder-worm. 

(Stiles.) 

free,  work  their  way  into  the  liver,  lungs,  brain,  or  other  organs, 
and  produce  tumors  which  sometimes  reach  a  large  size.  Several 
species  are  found  in  domestic  birds,  one  causing  epidemics 
among  chickens.  A  variety  of  Tce'nia  coenu'nis,  in  the  brain  of 
sheep,  causes  "  staggers."  Rabbits,  horses,  cats,  mice,  and 
rats  are  also  infested  by  tapeworms. 


CLASS  IV.     NEMERTINEA 

(Doubtful  Platyhelminthes) 
The  Nemertineans  are  most  abundant  in  the  mud  or  under 
stones  along  the  seashore,  only  a  few  species  living  in  fresh 
water.     They  differ  from  all  other  Platyhelminthes  in  having 


40  BRANCH    PLATYHELMINTHES 

an  alimentary  tract  with  an  anal  opening  and  a  distinct  blood- 
vascular  system.^     They  are  usually  dioecious.- 

Geographic  Distribution, — This  branch  of  animals  is  the  most 
widely  distributed  of  any  above  the  protozoans.  They  are 
found  on  land,  in  streams,  and  in  the  depths  of  lake  and  sea. 
The  parasitic  forms  are  found  in  some  stage  in  almost  every  class 
of  metazoans,  while  others  have  a  commensal  life  with  ascidians. 
All  are  carnivorous. 

Economic  Importance.^ — Many  domestic  animals  are  hosts 
for  these  parasites  and  much  loss  is  occasioned  thereby.  A 
number  of  class  Cestoda  are  parasitic  in  man  and  cause  annoy- 
ing if  not  dangerous  diseases.  The  only  sure  preventive  of  these 
parasites  is  to  have  all  meats  thoroughly  cooked  and  fruits  and 
vegetables  well  washed. 

Important  Biologic  Facts. — An  anterior  end — one  placed 
foremost  in  locomotion — and  a  posterior  end  appear  for  the  first 
time  in  platyhelminthes.  Also  right  and  left  and  dorsal  and 
ventral  sides  are  found. 

In  the  Nemertinea  there  is  an  alimentary  tract  with  a  mouth 
and  an  anal  opening.     There  is  no  distinct  coelom. 

Class  Turbellaria  is  the  most  primitive  and  the  most  closely 
related  to  the  Coelenterates,  but  it  is  not  thought  to  be  derived 
from  them,  though  it  shows  special  points  of  resemblance  to  the 
Ctenophora.  It  is  thought  that  Trematoda  and  Cestoda  are 
descendants  of  Turbellaria.  In  Trematoda  is  seen  an  alterna- 
tion of  generations  consisting  of  the  succession  of  several  dis- 
tinct generations  in  regular  series.  Such  an  alternation  of  gen- 
erations is  termed  heterogeny.  The  simple  structure  of  parasitic 
forms  illustrates  the  principle  that  easy  life — one  requiring 
little  exertion — is  accompanied  liy  a  low  stage  of  development. 

Classification. — 

Class.  Examples. 

I.  Turbella'ria.  Planarians. 

.     II.  Tremato'da.  Liver-fluke. 

III.  Cesto'da.  Tapeworms. 

IV.  Nemertin'ea.  Carinella,  Tetrastemma,  etc. 

1  MrMiirrifh,  p.  160;  Osborn's  "Economic  Zoology,"  p.  8.5;  Kingsley's 
Hertwig,  ]).  289. 

2  "Invertebrate Zoology,"  McMurrich, p.  162;  ParkerandHaswell,p.279. 


BRANCH   NEMATHELMIN'THES 

Round-  or  Thread-worms.— The  worms  of  this  branch  are 
elongated  and  cyUndric  and  have  a  coelom  or  body  cavity. 
The  vinegar-eel  affords  a  good  example.  They  differ  from 
annelids  in  that  they  are  not  divided  into  segments  or  rings. 

CLASS  I.     NEMATODA 

The  members  of  class  Nemato'da  are  best  known  as  para- 
sites, but  there  are  many  fresh-water  and  marine  forms. 

The  tough  body  wall  encloses  a  body  cavity  which  surrounds 
a  straight  alimentary  tube  having  a  terminal  mouth  and  a 
ventral  anal  opening.  An  excretory  system  is  usually  present. 
The  nervous  system  consists  of  an  esophageal  nerve  ring  which 
sends  out  six  nerves  anteriorly  and  six  posteriorly.  The  only 
sense  organs  are  sensory  papillae  on  the  lips.  The  sexes  are 
usually  separate.  Many  of  the  aquatic  forms  are  free.  Some 
of  the  parasites  infect  plants,  as  Tylen'chus  trit'ici,  which  does 
great  damage  to  wheat,  and  Heterode'ra  schach'tii,  to  turnips  in 
Europe. 

One  form,  Ascaris  nigrovenosa,^  living  a  parasitic  life  in  the  lungs  of 
frogs  and  toads,  is  hermaphroditic.  The  embryos  reach  the  alimentary 
canal  and  pass  out  with  the  waste  material.  In  water  they  develop  into 
a  stage  in  whieh  the  sexes  are  separate.  The  eggs  dcveloji  in  the  body  of 
the  female  and  devour  the  entire  substance  of  the  tissue  of  the  mother, 
leaving  only  the  cuticle.  When  set  free  they  live  in  the  mud  until  they 
are  taken  into  the  mouth  of  a  frog,  when  they  pass  into  the  lungs  and 
develop  into  the  hermaphroditic  stage.  Here,  again,  is  a  peculiar  alterna- 
tion of  generations  (heterogeny),  the  alternation  of  an  hermaphroditic  with 
a  dioecious  form. 

Trichinel'Ia  spiralis  (Fig.  31)  is  another  member  of  this  class.  In  the 
adult  stage  it  lives  in  the  alimentary  canal  of  man  or  of  other  mammals. 
The  length  of  the  adult  male  is  about  jV  inch,  and  that  of  the  female  about 
5  inch.  The  sexes  are  separate.  The  young,  at  least  one  thousand,  are 
born  alive.  The  young  worms  (Figs.  32,  33)  pass  through  the  intestinal 
wall  and  make  their  way  to  the  voluntary  muscles,  where  they  penetrate 
the  sarcolemma  and  become  encysted. 

1  Parker  and  Haswell,  vol.  i.,  p.  286.     McMurrich,  p.  176. 

41 


42 


BRANCH    NEMATHELMINTHES 


embr- 


Fig.  32.^ — Larvae  of  TrichineUa  spiralis  in  mus- 
cle, not  yet  encysted;  enlarged.     (Leuckart.) 


Fig.  33. — Piece  of  pork  showing  larva;  of 
TrichineUa  spiralis  encysted  in  the  muscle- 
fibers;  natural  size.     (Ostertag.) 


Fig.  31. — TrichineUa 
spiralis.  Adult  female, 
showing  embryos,  emh.,  in 
uterus;  gp.,  genital  o])en- 
ing  through  which  th(> 
embryos  are  discharged; 
enlarged.     (Leuckart.) 


Fig.  34.— Encysted  larva  of  TrichineUa  spira- 
lis; enlarged.     (Leuckart.) 


NEMATODA 


43 


When  the  infested  flesh,  unless  thoroughly  cooked,  is  eaten  by  man  the 
cysts  are  dissolved,  the  young  entering  the  small  intestine,  the  worms  con- 
tinue developing  and  become  sexually  mature  in  a  few  days,  the  female 
penetrates  into  the  superficial  layer  of  the  intestinal  villi,  and  in  the  course 
of  a  month  gives  birth  to  young,  and  then  dies.  The  young  wander 
through  the  lymph-vessels  and  blood-vessels  into  the  capillaries,  pass  into 
the  muscle  and  bi'cunic  encysted  (Fig.  34),  as  did  the  parents  in  the  former 
host;  1  ounce  of  inlesied  |)wik,  unless  thoroughly  cooked,  may  liberate 
80,000  worms.  If  lialf  of  t  liese  were  females,  each  producing  1000  embryos, 
40,000,000  worms  would  shortly  begin  to  migrate  into  the  muscles,  causing 
trichinosis,  which  may  be  fatal.  The  worst  epidemic  known  was  in  Emmers 
Leben,  Saxony,  in  1884,  where  364  persons  were  infected  from  eating  one 
pig,  and  57  persons  died  within  a  month. 

The  Guinea-worm  {Dracun/culus  medineiV sis)  is  an  East  India  parasite 
in  the  subcutaneous  connective  tissue  of  man.  It  is  long  and  slender, 
sometimes  1  yard  long.  It  forms  abscesses  under  the  skin.  When  the 
newborn  young  pass  out  of  their  host,  if  they  pass  into  water,  they  enter 
the  body  of  a  small  crustacean  (the  Cy- 
clops), which  is  necessary  to  their  develop- 
ment. It  is  supposed  that  they  reach 
the  human  system  through  the  Cyclops, 
which  is  swallowed  in  unfiltered  drinking- 
water. 


Fig.  35. — Eggs  of  the  gape-worm 
{Syn'gamus  trachea^lis),  one  of  them 
hatching;  enlarged  260  times. 
(After  Megnin.) 


Fig.  36. — Windpipe  of  chicken 
split  open  to  show  gape-worms  at- 
tached to  its  inner  surface;  en- 
larged.    (After  Megnin.) 


The  hook-worm  {N ecu' tor  nmerica'nus),  of  the  Southern  United  States 
and  the  West  Indies,  is  thought  to  have  been  introduced  from  Africa  by 
slaves.  "It  is  about  \  to  i  inch  long  and  about  as  thick  as  a  small  hairpin." 
—Stiles. 

"In  hook-worm  disease  we  have  ground-itch,  tibial  ulcer,  anemia,  inter- 
ference with  phvsical  and  mental  development,  and,  in  bad  cases,  dirt 
eating."— Stitt,  244. 

Other  Species. — There  arc  various  dtlier  s]H>cies.  Some,  as  the  pin-worm 
{Oxi/uris  I'l  rinicidaris)  and  tlie  louml-woi-ni  ( ,l.s'(f///N  liuiihricni'ili  s),  are 
parasitic  in  man.  Some  are  i)arasitic  in  other  nianunals  and  some  in  birds. 
One  of  the  latter,  Syn'gamus  IracfLca'lis  (Fig.  35),  about  2  inch  in  length, 
causes  "gapes"  in  poultry  (Fig.  36). 


44  BRANCH    NEMATHELMINTHES 

Gordius,  the  "  hair-worm,"  is  found  in  watering-troughs  and  erroneously 
believed  by  superstitious  people  or  those  ignorant  of  biologic  principles  to 
be  horse  hairs  transformed  into  live  worms.  The  larva;  are  parasitic  in 
the  grasshopper,  the  adults  live  in  water.  Agassiz  tells  of  experimenting 
with  one  18  inches  long  which  was  wrapped  in  and  out  of  its  eggs,  which 
were  rolled  up  into  a  ball  about  the  size  of  a  coffee  bean.  He  disentangled 
it  and  it  "  sewed  "  itself  through  and  through  the  little  white  mass.  Three 
times  he  separated  the  worm  from  its  eggs,  and  each  time  the  process  of 
entangling  was  repeated,  convincing  Agassiz  that  there  was  a  definite 
purpose  in  its  attempts,  and  that  even  a  being  so  low  in  the  scale  of  animal 
existence  has  some  dim  consciousness  of  a  relation  to  its  offspring. ^ 

He  placed  a  small  portion  of  the  egg  mass  under  the  microscope,  and 
estimated  that  there  were  not  less  than  8,000,000  eggs  in  the  whole  mass, 
which,  when  unwound,  made  a  string  12  feet  long. 


CLASS  II.     ACANTHOCEPHALA 

Most  of  the  class  Acan'thoceph'ala  are  small  parasites.  The 
chief  genus  (Echinorhyn'chus)  is  parasitic  in  the  intestines  of 
mammals,  birds,  reptiles,  amphibians,  and  fishes.  The  largest 
species  is  found  in  the  pig,  and  one  species,  Echinorhynchus 
hominis,  is  extremely  rare  in  man. 

CLASS  m.     CH^TOGNATHA 

This  class  contains  but  two  genera  of  curious  arrow-shaped 
worms,  all  but  one  species  of  which  are  pelagic.  They  are 
hermaphroditic  and  have  three  pairs  of  ccelomic  pouches, 
"  fins,"  and  bristle-like  jaws. 

Economic  Importance. — In  this  branch  may  be  found  worms 
which  are  harmful  and  those  which  are  helpful  to  man.  Those 
forms  like  TrichineUa  spiralis,  which  are  parasitic  in  man,  are 
very  injurious.  The  only  preventive  upon  which  it  is  safe  to 
rely  is  thorough  cooking. 

Those  forms  which  infest  wheat  and  turnips  are  also  harmful 
to  man,  in  that  they  destroy  his  food;  while  Gordius,  which  is 
parasitic  in  the  grasshopper,  is  indirectly  beneficial  to  man. 

Important  Biologic  Facts. — For  the  first  time  in  the  scale  of 
animal  life,  a  ccelotn,  or  body  cavity,  appears.  It  is  filled  with  a 
clear  fluid,  and  through  it  extends  the  straight  alimentary  tube 
which  consists  of  pharynx  or  stomodeum,  an  intestine,  and  a 
rectum.     There  are  no  circulatory  and  no  respiratory  organs. 

^  "Methods  of  Study  in  Natural  History,"  Agassiz,  pp.  63,  64. 


CHyI^]TOGNATHA  45 

This  })ranch  presents  similarities  to  both  Platyhelminthes 
and  Annulata,  but  the  relationship  with  either  is  not  close. 
Classification. — 

Class.  Examples. 

I.  Nemato'da.  Trichina,  Gordius. 

II.  Acan'thoceph'ala.^  Echinorhynchus. 

III.  Chaetog'natha.i  Sagitta. 

i"The  affinities  of  the  Acanthocephala  and  Chaetognatha  with  the 
Nematoda  are  somewhat  doubtful,"  Parker  and  Haswell's  "Zoology,"  vol. 
i,  p.  275. 


BRANCH  TROCHELMIN'THES 


The  animals  associated  together  in  this  group  may  have  de- 
veloped independently  from  trochosphere-like  ancestors,  but 
since  they  agree  in  general  character- 
istics, they  have  been  regarded  by  some 
as  constituting  a  well-marked  phylum. 
On  account  of  their  size  they  were 
formerly  regarded  as  protozoans,  but 
they  are  multicellular  and  possess  well- 
defined  digestive,  excretory,  nervous,  and 
reproductive  systems.  They  have  no 
circulatory  system.  Respiration  takes 
place  through  the  surface  of  the  body. 

CLASS   I.     ROTIFERA 

The  Rotifera  (Fig.  37),  or  "wheel 
animacules,"  are  many-celled,  micro- 
scopic, unsegmented  animals,  most  of 
which  are  worldwide  inhabitants  of  fresh- 
water ponds  and  streams,  or  even  of  mud- 
puddles  and  water-troughs.  A  numljer 
of  forms  are  marine. 

The  anterior  end  is  a  retractile  disk 
surrounded  by  cilia,  which  are  locomotive 
organs  as  well  as  aids  to  securing  food. 
The  mobile  tail  is  often  composed  of  tele- 
scopic rings,  rendering  it  retractile  into 
the  trunk.     The  posterior  ring  of  the  tail 
frequently  has  a  pair  of  pincer-like  stylets. 
These  and  the  adhesive  glands  enable 
the    rotifer  to  attach  itself   to  objects. 
There  is  a  crelom.     The  alimentary  tube  consists  of  a  ventral 
mouth,  an  esophagus,  a  chewing  apparatus  (m.astax),  a  glandular 
stomach,  and  an  intestine  which  ends  in  a  dorsal  anal  opening. 

46 


Fig.  37.— A  rotifer, 
highly  magnified  (Hy- 
datina  senia):  A,  cilia; 
a,  anus;  b,  contractile 
vesicle;  c,  water-ves- 
sels; e,  ovary;  /,  gang- 
lion. (From  Holder*s 
"  Elements  of  Zool- 
ogy," American  Book 
Co.,  Publishers.) 


GASTROTRICHA  47 

The  nervous  system  consists  of  a  dorsal  ganglion  with  which 
are  connectetl  one  or  more  eye-spots.  There  are  peculiar  tactile 
organs  which  consist  of  "  rod-like  structures  tipped  with  deli- 
cate sensory  hairs."  There  are  excretory  and  reproductive 
organs. 

They  are  dimorphic  (of  two  forms).  The  sexes  are  separate. 
The  males  are  rarer,  much  smaller,  and  less  highly  developed 
than  the  female.  The  female  lays  thin-shelled  summer  eggs 
of  two  sizes — the  larger  developing  into  females,  the  smaller  into 
males — and  thick-shelled  winter  eggs,  which  in  the  spring  de- 
velop into  females. 

The  majority  are  free  swimming,  being  propelled  by  the 
trochal  disk,  but  the  Bdelloida  also  have  a  looping  movement 
like  that  of  the  leech. 

The  rotifers  may  be  dried  up  in  the  mud  for  several  months, 
and  upon  being  brought  into  contact  with  water  they  revive,  or, 
some  think,  their  contained  eggs  bring  forth  live  animals. 
When  in  the  dry  condition  they  may  be  carried  long  distances  on 
the  feet  of  birds  or  by  the  wind. 

CLASS   II.     DINOPHILEA 

These,  like  the  rotifers,  are  modified  trochospheres.  They  are  minute 
and  worm-like.  They  have  a  prostomium  or  head,  a  body  of  five  to  eight 
segments,  and  a  short  tail.  Both  the  body  and  the  head  are  ciliated.  The 
Dinophilea  are  marine.  In  the  arrangement  of  the  nephridia  in  pairs, 
corresponding  to  the  imperfect  segments,  and  in  the  tendency  to  seg- 
mentation, they  resemble  the  Annulata. 

CLASS   III.     GASTROTRICHA 

This  class  resembles  the  Rotifera,  though  the  relationship  is  not  close. 
The  class  comprises  a  small  number  of  minute  fresh-water  forms  with 
spindle-shaped  bodies,  flattened  ventrally.  The  dorsal  surface  bears 
several  rows  of  cuticular  processes,  while  the  ventral  surface  has  two  rows 
of  cilia. 

Classification. — 

Class.  Examples. 

I.  Rotifera.  Brachionus. 

II.  Dlnophirea.  Dinophilus, 

III.  Gastrot'richa.  Ichthydium. 


BRANCH  MOLLUSCOIDA 

In  this  branch  there  is  usually  a  hotly  cavity,  with  the  ah- 
mentary  tube  suspended  by  mesenteries.  The  mouth  and  anal 
aperture  are  near  together,  the  dorsal  surface  being  shortened. 
In  the  atlult  there  is  a  tentacle-bearing  ridge,  or  lophophore,  about 
the  mouth,  containing  a  compartment  of  the  body  cavity. 
The  tentacles  are  used  not  only  in  securing  food,  but  in  respira- 
tion. The  nervous  system  consists  of  one  or  two  ganglia  or  of  a 
nerve  ring.^ 

CLASS   I.     POLYZOA 

MoUuscoi'da,  which  usually  form  colonies  of  zooids  by  budding,  are 
Pdlyzf/a.^  The  character  of  the  colony  differs,  according  to  the  mode  of 
budding  in  the  different  species  and  the  character  of  the  exoskeleton.  It 
varies  from  a  bush-like  colony  to  a  calcareous  or  gelatinous  sheet.  Each 
zooid  has  a  crown  of  ciliated  tentacles  which  can  be  extended  or  with- 
drawn. They  are  held  together  by  the  common  exoskeleton  formed  by 
the  ectoderm.  There  is  no  vascular  system.  The  digestive  tract  is  bent 
like  the  letter  U,  the  anal  opening  being  near  the  mouth,  within  or  just 
outside  of  the  ring  of  tentacles.  The  nervous  system  consists  of  a  gang- 
lion situated  between  the  mouth  and  the  anal  opening.  Polyzoans  are 
usually  hermaphroditic. 

CLASS  n.     PHORONI'DA 

The  classification  of  this  group  of  worm-like  forms  of  the  sea  is  doubtful. 

The  worm  is  covered  by  a  leathery  cylindric  tube  into  which  it  may 
withdraw.  The  body  is  unsegmented  and  bears  a  crown  of  tentacles. 
The  mouth  and  anus  are  close  together  and  are  situated  at  the  tentacle- 
bearing  end  of  the  body.  The  body  cavity  is  divided  into  three  chambers. 
There  is  an  alimentary  tract  and  a  closed  system  of  blood-vessels  contain- 
ing red  blood-corpuscles.  The  central  nervous  system  consists  of  a  horse- 
shoe-shaped nerve  ring  at  the  base  of  the  tentacles.  The  Phoronis  is 
hermaphroditic.     There  is  a  metamorphosis. 

CLASS   m.     BRACHIOP'ODA 

Brachiopods  are  marine  and  were  abundant  in  former  geologic  times, 
being  very  plentiful  as  early  as  the  Cambrian  Period.  There  are  a  few 
living  species. 

They  are  enclosed  in  a  bivalve  shell  (Fig.  38),  the  valves  being  dorsal 
and  ventral  instead  of  right  and  left,  as  in  the  mollusks.     They  are  at- 
tached to  foreign  objects  by  a  -peduncle  or  stalk,  which  passes  through  the 
larger  or  ventral  valve  near  the  hinge.     They  do  not  form  colonies. 
1  Parker  and  Haswell,  p.  313. 
48 


BRACHIOPODA 


49 


The  shell  is  only  partially  tilled  by  the  body,  and  the  valves  are  lined 
by  the  mantle  lobes,  whose  tree  edges  are  bristled.  The  mantle  lobes 
enclose  a  large  mantle  ca\il\'.  In  the  body  is  a  spacious  cffilom,  which  is 
extended  into  the  mantle  lobes.  The  ca4om  contains  the  digestive  tract, 
the  liver,  and  the  reproductive  organs.  The  latter  are  chiefly  in  the 
mantle  lobes.  The  digestive  tract,  which  is  bent  much  as  in  the  Polyzoa, 
consists  of  gullet,  stomach,  and  intestine.  The  mouth  is  surrounded  by  the 
tentacled  lophophore  or  "  arms."  The  inner  surface  of  the  tentacles  is 
covered  with  cilia,  which  set  up  currents  in  the  water  and  sweep  minute 
animals  and  algae  into  the  mouth  for  food.     The  heart,  usually  present,  lies 


Fig.  38. — Diagram  of  a  brachioi)od :  b,  Tentacles  around  mouth,  ??i;  i, 
intestine;  the  shell  black,  the  stalk  to  the  right.  (Kingsley's  "Compara- 
tive Zoology,"  Henry  Holt  &  Co.,  Publishers.) 

dorsal  to  the  stomach,  to  which  it  is  attached.  The  nervous  system  con- 
sists of  an  esophageal  ring.  Sense  organs  are  usually  wanting  in  the 
adult. 

Important  Biologic  Facts. — For  the  first  time,  according  to 
the  classification  used,  a  closed  system  of  blood-vessels  and 
red  blood-corpuscles  are  found. 

The  digestive  tract  has  been  developed  into  gullet,  stomach, 
and  intestine,  and  a  liver  also  appears. 

The  Brachiopoda  were  formerly  supposed  to  belong  to  branch 
Mollusca.  But  the  valves  of  the  shell  are  dorsal  and  ventral, 
not  right  and  left,  while  the  tentacled  lophophore,  the  character 
of  the  nephridia,  and  the  modified  trochosphere  larva  all  tend 
to  show  relationship  with  members  of  branch  Molluscoida. 

Classification. — 


Class. 
I.  Polyzo'a. 

II.  Phoroni'da. 
III.  Brachiop'oda. 
4 


Example. 
Bugula  avicularia   (Bird's-head 

Coralline) . 
Phoronis. 
Magellania. 


BRANCH   ECHINODER'MATA 

Plan  of  Structure. — These  animals  are  characterized  by  their 
five-rayed  or  pentameral  plan  of  structure.  While  the  echino- 
derm  is  radially  symmetric,  the  development  shows  that  it  is 
derived  from  the  bilateral  type.     The  larvce  are  bilateral.     The 


Fig.    39. — Solas' ter    endeca    (small   specimen,    natural   size),  oral    view. 
(Bulletin,  U.  S.  F.  C,  1902.) 


central  portion  is  the  disk,  from  which  arms  or  rays  project,  as 
seen  in  the  starfish.  Close  examination  will  reveal  this  penta- 
merous  plan  in  the  sea-urchin  and  in  the  sea-cucumber.  For, 
suppose  the  rays  of  the  starfish  were  flexed  and  their  edges 
joined,   the  form  of    the    sea-urchin    would    appear.     Again, 

50 


GEOGRAPHIC    DISTRIBUTION 


51 


lengthen  the  sea-urchin  in  the  direction  of  the  mouth  to  aboral 
surface,  and  you  have  the  form  of  the  sea-cucumber.  The 
crinoid  also  reveals  this  plan,  not  so  clearly  defined,  but  it  is  to 
be  seen  by  the  careful  observer.  The  number  of  rays  varies  in 
the  starfish,  the  author  having  found  them  with  four,  six,  or 
even  as  many  as  twenty-two  rays. 


Fig.  40. — 1  and  2,  Amphipholis  squamata  (adult),  aboral  and  oral  views. 
3  and  4,  Asterias  vulgaris  (small  specimen),  aboral  and  oral  views.  (Bul- 
letin, U.  S.  F.  C,  1902.) 


The  Skeleton  or  "Tesi." — The  body  wall  is  composed  of  a 
thick  leathery  substance.  In  the  mesoderm,  under  the  epi- 
thelium, calcareous  plates  arise,  many  of  which  are  armed  with 
spines  for  protection.  They  are  greatly  protected  also  by  their 
resemblance  to  their  environment. 

Geographic  Distribution. — All  echinoderms  are  marine,  being 
abundant  oven  in  the  deep  sea.  They  are  found  in  all  parts  of 
the  globe,  but  are  most  abundant  in  the  tropics.  At  the  breed- 
ing season  most  of  the  free  species  frequent  the  shallow  waters 


52 


BRANCH    ECHINODEUMATA 


near  the  coast,  where  the  ova  are  fertihzed  in  the  water.    Echiuo- 
derms  of  the  same  species  are  often  gregarious. 

The    water-vascular   system  is   a  marked   characteristic   of 
echinoderms   (Fig.   41).      It   begins  externally   with   the  cal- 


-eye  spot 


eye  spot  ■ 


Pyloric  itutitm 
'muscles  of  ike  pyloric  caeca 
Fig.  41. — Dissection  of  a  starfish  {Asterias  sp.)-     (From  Kellogg.) 


careous  perforated  madreporic  plate  which  is  connected  by  a 
calcareous  (Stone)  canal  with  the  central  ring  around  the 
mouth,  from  which  tubes  proceed  along  each  arm,  in  the  star- 


METAMORPHOSIS  53 

fish.  On  the  inside  of  tlie  floor  of  each  ray  are  the  ampidlce, 
small  bulb-like  water-sacs,  which  are  connected  with  the  tube- 
feet  on  the  outside  of  the  ray.  "  By  a  contraction  of  the  deli- 
cate muscles  in  the  walls  of  the  ampullae  the  fluid  in  the  cavity 
is  compressed,  thereby  forcing  the  tube-feet  out.  By  the  con- 
traction of  muscles  in  the  tube-feet  they  are  again  shortened, 
while  the  small  disk-like  terminal  sucker  clings  to  some  firm 
object.  In  this  way  the  animal  pulls  itself  along  by  successive 
steps."  By  the  aid  of  these  ambulacral  or  tulje-feet  the  starfish 
is  able  to  turn  over  if  placed  upon  its  back.  They  also  act  as 
suckers  to  fasten  the  starfish  to  the  rocks.  When  once  this  is 
accomplished,  arm  after  arm  may  be  broken  off  before  the 
animal  can  be  pulled  loose  or  the  feet  will  relax  their  hold. 

So-called  blood  canals  accompany  the  ring  and  radial  canals, 
and  associated  with  them  are  sometimes  two  intestinal  blood- 
vessels. ^ 

Nervous  System. — "  There  is  a  nerve  ring  and  radial  nerve, 
frequently  in  the  ectoderm,  to  which  may  be  added  an  entero- 
ccelic  or  apical  nervous  system,  possibly  of  peritoneal  origin." 

The  circulating  fluid  is  somewhat  lymph-like  and  the  circula- 
jtion  slow. 

"  Respiratory  organs  are  represented  by  the  hranchicp,  or  thin- 
walled  outpushings  of  the  coelom,  either  around  the  mouth,  as  in 
the  Echinoi'dea,  or  on  the  aboral  surface,  as  in  the  Asteroi'dea, 
the  bursce  of  the  Ophiuroi'dea,  the  branchial  trees  of  the  Holothu- 
roi'dea,  and  the  various  parts  of  the  ambulacral  system."- 

The  alimentary  tube  is  complete,  that  is,  shut  off  from  the 
body  cavity  and  runs  through  the  body.  Its  length  depends  upon 
the  food  of  the  echinoderm.  In  carnivorous  forms,  as  the  star- 
fish, it  is  short,  but  in  vegetable  feeders,  as  the  sea-urchins 
and  sea-cucumbers,  the  alimentary  tube  is  two  or  three  times 
the  length  of  the  body. 

Multiplication  is  sexual,  as  a  rule,  the  sexes  being  separate 
except  in  rare  cases.  Fertilization  takes  place  in  the  water. 
They  never  form  colonies  by  budding. 

The  metamorphosis,  or  change  from  the  larval  to  the  adult 
form,  is  as  marked  as  that  from  the  caterpillar  to  the  butterfly. 

^  Hertwig's  "  Manual  of  Zoology,"  Kingsley,  p.  331. 
2  Ibid. 


^ 


54  BRANCH    ECHINODERMATA 

The  larva  is  bilateral/  while  the  adult  is  radial,  the  develo]mient 
being  complex. 

Generally  the  young  shift  for  themselves,  but  cases  are 
recorded  of  broods  being  cared  for  by  the  female  echinoderm 
in  a  pouch  on  the  dorsal  surface. 

CLASS   I.     ASTEROIDEA 

To  this  class  belong  the  starfishes,  with  their  central  disks 
and  varying  number  of  rays,  five  being  the  typical  number. 
They  live  along  rocky  seacoasts.  Fresh  water  kills  them. 
The  common  starfish  (Aste'rias  vulga'ris)  is  abundant  along  the 
Atlantic  coast,  especially  in  the  vicinity  of  oyster-beds,  to 
which  they  do  much  injury  by  devouring  the  oysters.  Star- 
fishes are  found  also  on  the  Pacific  coast  from  Sitka  to  southern 
California.  They  are  said  to  devour  small  fishes  as  well  as 
crabs. 

The  body  wall  is  composed  of  a  thick  leathery  substance  m 
which  is  embedded  a  great  number  of  calcareous  ossicles 
(12,000  by  estimation),  many  of  which  are  armed  with  spines 
for  protection.  Between  the  spines  on  the  aboral  surface  are 
soft  stalked  projections  ending  in  pinchers,  called  pedicella'rice, 
with  which  it  cleanses  the  surface  of  the  body  and  protects 
itself  from  parasites. 

The  alimentary  tube  extends  from  the  oral  to  the  aboral 
surface.  It  consists  of  a  mouth,  a  short  esophagus,  and  a  large 
sac-like  stomach,  which  is  five  lobed  and  fills  most  of  the  disk. 
(See  Fig.  41,  p.  52.)  The  stomach  is  eversible  and  is  furnished 
with  muscles  for  withdrawing  it.  From  the  pyloric,  or  upper, 
division  of  the  stomach  the  cmca  extend,  a  pair  into  each  arm. 
These  caeca  secrete  much  fluid,  which  is  emptied  into  the 
pyloric  portion  of  the  stomach  and  used  in  chgesting  the  food. 
From  the  stomach  a  short  conical  intestine  extends  upward 
to  the  aboral  surface.  The  aboral  opening  from  the  intestine  is 
not  exactly  in  the  center  of  the  disk  and  is  often  difficult  to  find. 
In  a  few  forms  it  is  wholly  obliterated. 

Locomotion. — The  arms  are  somewhat  flexible,  and,  aided  by 
their  tube-feet, ^  enable  the  starfishes  to  move  slowly  along  in 

1  Hertwig's  "Manual  of  Zoology,"  Kingsley,  p.  331. 

^  See  text,  Water-vascular  System  of  Echinoderms,  p.  52. 


ASTEROIDEA 


55 


search  of  food.  The  starfish,  by  cHnging  with  its  sucking  disks, 
can  travel  along  horizontal  or  vertical  walls  It  can  bend  its 
arms  or  even  its  central  disk,  when  necessary,  to  pass  through 
openings  or  crevices  between  rocks.  As  it  moves  so  slowly,  its 
direct  dispersal  is  very  limited,  but  since  it  is  not  attached,  it  is 
indirectly  distributed  by  the  tides  and  currents.  The  exceed- 
ingly minute  young  are  often  borne  great  distances  in  this  way. 
Foods  and  Feeding. — The  starfish  is  carnivorous  and  very 
voracious;  indeed,  it  seems  to  eat  continuously.  It  feeds  upon 
barnacles,  clams,  oysters  (Fig.  42),  and,  it  is  said,  even  small 
fishes,  or,  failing  of  these,  it  will  eat  the  garbage  thrown  along  the 
shore,  thus  acting  as  a  sort  of  scavenger.     The  worst  damage  it 


Fig.  42. — Starfish  attacking  oysters.     (From  Fifth  Report  of  Connecticut 
Bureau  of  Labor  Statistics.) 

does  by  its  gluttony  is  to  the  oyster-beds.  Oysters  and  clams 
close  their  shells  to  the  starfish,  but  it  keeps  up  a  stea:dy  ])ull  un- 
til it  gets  them  open,  when  it  reaches  its  arms  about  its  prey  and 
extrudes  the  lower  part  of  its  stomach,  envelops  the  soft  parts, 
pours  out  the  digestive  fluids  about  them  and  absorbs  them, 
then  withdraws  its  stomach,  leaving  the  indigestible  parts  of  its 
victim  outside  the  l^ody.  Further  digestion  of  the  absorbed  food 
takes  place  in  the  pyloric  portion  of  the  stomach,  aided  by  the 
secretions  of  the  hepatic  cseca.  The  fact  that  all  indigestible 
parts  are  ''  rejected  "  may  account  for  the  shortness  of  the  in- 
testine, and  certainly  does  account  for  the  small  or  lacking  anal 
aperture,  since  there  is  little  left  to  be  "  ejected." 


56  BRANCH    ECHINODERMATA 

The  nervous  system  consists  of  a  circumoral  nerve  ring, 
from  which  a  nerve  proceeds  along  the  ambulacral  groove  of 
each  arm  to  its  tip,  where  it  ends  in  a  so-called  "  eye-spot  " 
which  has  been  proved  sensitive  to  light. 

Special  Senses.— Besides  the  general  sense  of  touch  and  the 
"  eye-spots,"  already  mentioned,  there  is  at  the  distal  end  of 
each  ray  a  tentacle-like  organ  which  is  supposed  to  be  the  organ 
of  smell. 

Multiplication  is  sexual.  Fertilization  takes  place  in  the 
water.  The  starfish  may  reproduce  asexually,  for  if  a  ray  be 
broken  oftV  either  accidentally  or  purposely  by  the  animal 
itself,  it  has  the  power  of  reproducing  a  new  disk  as  well  as  the 
rest  of  the  arms,  with  their  internal  organs.  Similarly,  if  all 
the  arms  are  torn  off,  the  disk  has  the  power  of  growing  out  new 
ones.  The  young  are  bilaterally  symmetric,  free-swimming 
animals.  The  metamorphosis  is  complicated,  resulting  finally 
in  the  radial  plan  of  structure  of  the  adult. 

The  starfish,  Linckia  linckia,  is  a  host  for  a  parasitic  gastero- 
pod  (Thyca).     Some  starfishes  are  gregarious. 

In  size  they  vary  from  less  than  1  inch  to  3  feet  in  diameter. 
In  color  they  may  be  yellow,  brown,  red,  or  purple. 

Geologic  Distribution. — The  starfishes  appeared  before  the 
close  of  the  Caml^rian  Period,  and  have  been  represented  in 
every  age  up  to  the  present. 

CLASS   II.     OPHIUROIDEA 

These  echinoderms  resemble  the  starfish.  The  arms  are 
slender,  jointed,  muscular,  and  are  used  for  locomotion  (Fig. 
43).  The  arms  may  be  much  branched,  as  in  the  basket-fish, 
and  are  not  hollow  as  they  are  in  the  starfish.  The  ambulacral 
groove  is  closed,  the  tul)e-feet  are  on  the  sides  of  the  arms, 
and  have  no  suckers  at  their  distal  ends. 

The  arms  are  much  more  slender  and  more  flexible  than  those 
of  the  starfish,  and  locomotion,  which  is  faster  than  that  of  the 
starfish,  is  accomplished  l)y  the  lateral  movements  of  the  arms. 
Some  species  have  the  power  of  throwing  off  pieces  of  their 
arms  when  disturbed. 

The  digestive  organs  are  confined  to  the  disk,  the  hepatic 
1  Parker  and  Haswell,  p.  400. 


ophiuroidea"  57 

caeca  are  absent,  and  the  anal  opening  is  lacking.  The  madre- 
poric  plate  is  on  the  oral  side. 

Food. — They  are  carnivorous,  feeding  upon  worms,  crabs,  and 
sliell-fish.     They  are  also  scavengers. 

Multiplication. — Some  lay  their  eggs  in  the  water,  where  they 
are  fertilized  and  develop  into  a  pluteus  stage  like  that  of  the 


Fig.  43. — Gorgonocepl/alus  agassiz'ii  (one-fourth  natural  size).     Oral  view. 
(Clark,  in  Bulletin  550,  U.  S.  F.  C,  1902.) 

Echinoidea,  while  others  are  viviparous  and  care  for  their 
broods.  In  many  species  there  is  also  a  kind  of  asexual  repro- 
duction, the  animal  dividing  through  the  disk  and  each  half 
regenerating  its  "  other  half." 

There  are  several  hundred  species  known.     These  echino- 
derms  are  variously  called  brittle-stars,  serpent-stars,  and  sand- 


-    58 


BRANCH    ECH I NOD ERM ATA 


stars.     The  one  most  common  on  our  shores  (Ophiopholis)  is 
of  a  "  general  red  hue  spotted  with  brown  and  paler  red." 

CLASS   III.     ECHINOIDEA 

The  globular  or  disk-like  sea-urchins  have  the  pentameral 
plan,  as  a  cleaned  "  test  "  or  shell  (Fig.  44)  will  show. 

The  body  wall  is  composed  of  several  hundred  pentagonal 
calcareous  plates  arranged  in  regular  order  in  twenty  rows, 
the  whole  forming  a  sort  of  thin  case  or  shell  (see  Fig.  44). 


Fig.  44. — 8ea-urchiii  {Echi'iiun  micros' ioiiui)  with  .spines  nearly  all  removed 
from  "  test."      (Chapin  and  Rettger.) 


The  ossicles,  or  plates,  are  armed  with  very  long  sharp  spines 
for  defense  (Fig.  45).  Alternate  rows  of  plates  are  perforated 
for  the  passage  of  the  tube-feet,  there  being  no  grooves.  These 
ten  rows  of  perforated  plates  constitute  the  amlnilacral  areas, 
and  the  ten  rows  of  unperforated  plates  constitute  the  inter- 
ambulacral  areas. 

Color. — The  colors  are  ])r()wn,  olive,  pur])le,  red,  green,  or  l)lue. 

The  protective  resemblance  is  good. 

The  ambulacral  system  of  the  sea-urchin  is  similar  in  plan 


ECHINOIDEA 


59 


to  that  of  the  starfish.  Lot'omotion  is  very  slow  ami  is  per- 
formed by  the  tube-feet,  aided  by  the  long  spines. 

The  pedicellariae  are  similar  to  those  of  the  starfish,  but  are 
more  fully  develojied,  having  three  pinchers  instead  of  two. 

The  food  consists  largely  of  green  algcB  and  brown  seaweed, 
for  the  sea-urchin  is  a  vegetable  feeder,  though  it  eats  small 
marine  animals  also. 

Digestive  System. — There  are  five  hard  white  teeth  with 
which  they  gnaw  their  food.     These  teeth  are  connected  with  a 


Fig.   45. — Stro/igyluceitl) 
"  feet,"  and  teeth. 


utus  drnbachiensis.      Oral    view,    showing  spines, 
(Clark,  in  Bulletin  550,  U.  S.  F.  C,  1902.) 


complicated  calcareous  framework  under  muscular  control. 
The  whole  apparatus  is  called  "  Aristotle's  lantern." 

The  intestines  are  long,  coiling  about  two  and  a  half  to  three 
times,  instead  of  being  short  like  those  of  the  carnivorous  star- 
fish. 

The  hepatic  caeca  and  gastric  pouches  are  absent.  This 
lack,  as  well  as  the  structure  of  the  mouth  parts  and  the  long 
coiled  intestine,  correlates  with  the  feeding  habits  of  these 
herbivorous  animals. 


60  BRANCH    ECHINODERMATA 

The  nervous  system  is  upon  the  saine  i)lan  as  that  of  the 
starfisli. 

Multiplication. — The  eggs  are  laid  in  the  water  and  fertihzed 
by  the  tadpole-hke  sperm  cells.  Some  forms  have  a  marsu- 
pium,  or  brood-pouch,  in  which  the  eggs  are  hatched. 

Development. — After  fertilization,  segmentation  of  the  egg 
takes  place  until  the  bilaterally  symmetric  young  "  pluteus," 
which  .is  very  unlike  the  adult,  appears.  It  is  free  swimming 
and  lives  on  minute  organisms  it  can  procure  in  the  water.  As 
it  develops  it  takes  on  the  radiate  or  pentameral  plan  of  its 
branch.  The  "  sand  dollars  "  so  common  on  both  the  Pacific 
and  the  Atlantic  coasts  are  flat  sea-urchins  with  short  spines. 

Geologic  Distribution. — A  primitive  type  of  sea-urchin  ap- 
peared in  the  Ordovician  period.' 

CLASS   IV.     HOLOTHUROIDEA 

Holothurians  are  free,  and  a  close  examination  reveals  the 
pentameral  plan  of  the  l^ranch,  although  they  are  more  or  less 
bilaterally  symmetric. 


Fie.  46.— Cwcw/rta'na  f rondo' sa,  side  view.      Note  tentacles  and  rows  of 
feet.     (Clark,  in  Bulletin  r-^m,  U.  S.  F.  C,  1902.) 

The  shape  (Fig.  46)  is  much  like  that  of  the  garden  cucumber 
in  our  common  varieties,  but  some  are  long  and  slender  and 
1  Scott's  "Geology,"  p.  381. 


HOLOTHUROIDEA 


()1 


more  worm-like  in  appearance.     Some  are  so  long  and  slender 
that  they  are  sometimes  thought  to  be  worms. 

The  size  varies  from  |  inch  in  one  species  found  upon  the 
Massachusetts  coast,  to  3  feet,  in  another  species  found  in 
Monterey  Bay,  California. 

The  body  wall  is  tough,  leathery,  muscular,  and  not  so  rigid 
as  in  the  starfish  or  sea-urchin,  although  minute  calcareous 
spicules  are  scattered  throughout  it. 

The  tube-feet  may  be  in  rows,  or  scattered,  or  entirely  want- 
ing, depending  upon  the  species,  of  which  several  hundred  are 
recorded.       The    sea-cucumbers 
move  with  their  long  axis  parallel 
to  the  ground.     They  creep  along 
with  the  help  of  the  tentacles. 

Protective  Resemblance. — 
Their  colors,  which  are  reddish 
brown  or  yellowish,  harmonize 
so  closely  with  those  of  their  en- 
vironment that  their  protective 
resemblance  is  almost  perfect. 
As  the  animals  rest  on  the  bot- 
tom of  the  sea  with  their  feathery 
tentacles  spread  out  they  closely 
resemble  the  vegetation  of  the 
sea  bottom.  A  person  may 
stand  within  a  foot  of  the  sea- 
cucumber  and  not  see  it. 

The  alimentary  tube  (Fig.  47) 
is  several  times  the  length  of 
the  animal,  and  the  intestine  is 
coiled  in  a  uniform  manner. 

The  food  of  the  holothurians  consists  of  organic  matter 
obtained  from  the  sand  which  they  swallow,  or  of  small  animals 
which  they  capture  with  their  tentacles.  They  are  nocturnal 
in  their  feeding  habits,  resting  quietly  during  the  day  on  the 
bottom  of  the  sea  or  buried  in  the  sand. 

The  respiratory  system  consists,  probably,  of  the  so-called 
"  respiratory  trees,"  two  hollow,  much-branched  organs  open- 
ing into  the  cloaca,  which  is  periodically  filled  with  water. 


Fig.  47. — Sea-cucumber  ( Holo- 
thurian)  dissected  to  show  ali- 
mentary tube,  al.t.    (Leuckart.) 


62  BRANCH    ECHINODERMATA 

They  are  probably  excretory  organs  also,  and  are  connected 
with  the  manipulations  of  the  tentacles.^ 

Multiplication  is  generally  similar  to  that  of  the  starfish, 
except  in  rare  cases  of  hermaphroditism.  There  are  also  cases 
recorded  of  the  female  caring  for  her  brood  in  dorsal  pouches. 
In  unfavorable  conditions  they  void  the  whole  viscera  and  yet 
live  and  replace  the  lost  parts. ' 

In  the  development  from  the  bilateral  larva  to  the  radial 
adult  there  is  a  marked  metamorphosis. 

Several  species  are  hosts  for  certain  parasites.  A  small 
fish  infests  the  cloaca  and  branchial  trees  of  one  or  two  species. 
A  snail  lives  in  one  species  and  a  mussel  in  another. 

Use. — They  are  used  for  food  by  the  Malays,  who  call  them 
"  trepang,"  and  use  them  principally  for  soups.  Millions  of 
them  are  captured  in  the  south  seas,  where  hundreds  of  vessels 
are  engaged  in  the  trepang  fisheries. 

Distribution. — Holothurians  are  widely  distributed,  being 
found  from  the  arctic  to  the  tropical  regions. 

Geologically,  they  date  from  the  Carboniferous  Period. 

CLASS   V.     CRINOI'DEA 

Crinoids  are  fixed  echinoderms  with  a  flexible  stem  or  stalk 
of  calcareous  perforated  disks,  bearing  a  flower-like  body  at 
the  top  of  the  stem  (Fig.  48).  This  body  consists  of  a  cup- 
shaped  center  bearing  five  or  ten  arms,  usually  branched. 
The  "  feather  stars,"  found  at  a  less  depth,  later  become  de- 
tached and  float  around  in  the  water. 

Ambulacral  Grooves. — Five  ciliated  ambulacral  grooves 
(Fig.  49)  extend  from  the  mouth  out  on  the  arms  and  their 
branches,  and  give  off  branches  to  the  pinnules.  They  serve 
as  channels  through  which  the  food  passes  to  the  mouth,  and  also 
for  the  purpose  of  respiration. 

Food. — They  feed  on  small  crab-like  animals  and  on  marine 
unicellular  animals  and  plants. 

The  nervous  system  consists  of  a  nerve  ring  surrounding  the 
mouth,  and  given  off  from  this  nerve  ring  are  a  series  of  amliu- 
lacral  nerves  which  extend  the  entire  length  of  the  arms  and 
pinnules. 

1  Parker  and  Haswell's  "Zoology,"  vol.  i,  p.  372.  ^  ibjd.,  p.  400. 


CRINOIDEA 


63 


Fig.  4S. — Crinoid  {Podac'rinus),  half  natural  size.     (Brehm.) 


O^ 


~)V^*^f  "•^■^'^.^  c 


^M 


Fig.  49. — Mouth  area  of  a  crinoid  {Comafula),  showing  the  course  of  the 
intestine  leading  from  the  mouth  {m)  to  the  vent  (a);  g,  grooves  leading 
from  arms  to  mouth.  (From  Kingsley's  "  Comparative  Zoology,"  Henry 
Holt  and  Co.,  FubHshers.) 

Digestive  System. — The  mouth  is  directed  upward  and  leads 
into  the  digestive  tract,  consisting  of  esophagus,  stomach,  and 


G4  BRANCH    ECHINODERMATA 

intestines.  The  interradial  anal  opening  (see  Fig.  49)  is 
situated  near  the  mouth. 

Multiplication. — Crinoids  multiply  l)y  eggs,  which  puss 
through  complex  changes  before  reaching  the  adult  stage. 

Habitat. — The  living  crinoids  are  deep  sea  animals  with 
the  exception  of  two  genera,  which  live  at  a  less  depth.  Some 
have  been  dredged  from  a  depth  of  11,100  feet.  At  this  depth 
the  water  pressure  must  be  enormous. 

Geologic  Distribution. — Primitive  types  (the  cystids  and 
blastoids)  of  this  group  are  among  the  most  ancient  fossils. 
True  crinoids  appeared  before  the  close  of  the  Cambrian 
Period.  They  reached  their  culmination  in  the  Carboniferous 
Period.  The  crinoid  fossils  of  this  period  are  so  numerous  that 
many  beds  of  limestone  are  composed  principally  of  them. 
Burlington,  Iowa,  and  Crawfordsville,  Indiana,  are  noted  for 
their  numerous  and  well-preserved  fossil  crinoids.  Crinoids, 
though  formerly  of  such  vast  numbers,  are  now  almost  extinct. 

Important  Biologic  Facts. — Echinoderms  are  radially  sym- 
metric, but  embryology  shows  that  they  have  developed  from 
the  bilateral  type.  It  is  reasonable  to  regard  those  classes  of 
echinoderms  as  the  more  ancient  which  have  the  radial  sym- 
metry less  completely  developed.^ 

The  locomotor-ambulacral  system  is  found  in  no  other 
branch. 

The  echinoderms  are  a  singularly  isolated  group,  and  we 
look  in  vain  among  the  known  members,  living  and  fossils,  of 
other  branches  for  any  really  close  allies. 

Classification. — 


Class. 

Exam-ples. 

I. 

Asteroi'dea. 

Starfishes. 

II. 

Ophiuroi'dea. 

"  Brittle-stars." 

III. 

Echinoi'dea. 

Sea-urchins. 

IV. 

Holothuroi'dea. 

Sea-cucumbers. 

V. 

Crinoi'dea. 

Sea  Lilies,  "  Feather-stars." 

VI. 

Cystoi'dea. 

Fossil. 

VII. 

Blastoi'dea. 

Paleozoic  fossil,  as  in  Class  VI. 

1  Parker  and  Haswell's 

"Zoology,"  vol.  i,  p.  401. 

BRANCH  Mm^JLATk 

The  branch  Annula'ta  is  distinguished  from  the  other  branches 
of  worms  by  having  external  and  internal  segmentation,  that  is, 
being  divided  into  rings  or  segments  (metameres)  "  containing 
homologous  organs  or  similar  portions  of  a  continuous  organ."^ 

They  have,  usually,  a  well-developed  coelom  or  body  cavity, 
divided  into  segments  by  muscular  partitions  or  septa. 

These  worms  are  bilaterally  symmetric.  The  botly  is  usually 
elongated, 

CLASS   I.     CH^TOPODA 

Class  Chsetop'oda  consists  of  fresh-water  and  marine  annelids 
which  bear  setae,  or  bristles.  The  setae  arise  from  special  fol- 
licles, and  may  occur  singly  or  in  bunches.  These  setae,  which 
are  controlled  by  special  muscles,  act  as  tiny  levers  in  locomo- 
tion. 

They  have  a  body  cavity  which  is  partially  divick'd  into  com- 
partments corresponding  to  the  segments.  The  alimentary 
tube  extends  through  the  body  and  is  usually  constricted  at  the 
septa.  There  is  usually  a  well-developed  circulatory  system. 
Respiration  is  usually  through  gills  or  branchiae  and  through 
the  body  wall.  In  some  forms  the  sexes  are  distinct,  while 
other  forms  are  hermaphroditic.  Fresh-water  annelids  de- 
velop without  a  metamorphosis,  l)ut  in  many  marine  forms  the 
trochosphere  larvae  occur. 

Few  are  true  parasites,  but  a  number  are  commensal,  habitu- 
ally associating  with  other  animals  for  their  food  and  shelter. 
Many  sea-worms  are  phosphorescent. 

The  earthworm  {Lum'hricus)  has  an  elongated  eylindric  ])ody 
of  many  segments  or  metameres. 

Digestive   System   (Fig.   50). — The  mouth  is  covered  by  a 

rounded,    lolx'-like    ])rojection,    the    prostomium.     The   mouth 

leads  into  a  small  buccal  cavity,  back  of  which  is  the  larger. 

thick-walled,  muscular  pharynx.     This  pharynx  can  be  pro- 

^  Galloway's  "  Zoology." 

5  65 


66 


BRANCH    ANNULATA 


al.  t. 


truded  uiid  retracted.  The  radially  arranged  muscular  fibers 
which  run  from  the  pharynx  to  the 
body  wall  retract  the  pharynx  and  at 
the  same  time  dilate  it.  Back  of  the 
pharynx  is  the  narrow  esophagus,  with 
a  pair  of  pouches  and  two  pairs  of 
calciferous  glands,  which  communicate 
with  these  pouches  and  which  contain 
a  limy  fluid.  Posterior  to  the  pharynx 
is  the  thin-walled  crop,  and  back  of 
this  is  the  very  thick-walled  rounded 
gizzard,  with  its  tough,  chitinous  lin- 
ing, in  which  the  food  is  ground  by 
sand,  and  from  which  the  intestine  ex- 
tends to  the  anal  opening  in  the  pos- 
terior -segment. 

The  typhlosole,  a  prominent  ridge 
extending  along  th(>  middle  of  the  dor- 
sal surface  of  the  intestine  and  dipping 
down  into  the  interior,  renders  the 
hollow  of  the  intestine  crescent  shaped. 
This  typhlosole  increases  the  absorb- 
ing surface  and  is  well  supplied  wdth 
blood-vessels. 

The  circulation  is  carrried  on  in  a 
well-developed  system  of  blood-vessels. 
The  dorsal  tube  extends  along  the 
median  line  of  the  dorsal  surface  and 
is  plainly  seen  in  the  live  earthworm. 
The  forward  movement  of  the  blood  can 
usually  be  seen.  The  ventral  blood-ves- 
sel lies  below  the  alimentarj^  tube.  In 
this  ventral  V)lood-vessel  the  blood  is  j^ro- 
pelled  backward  by  the  peristaltic  action 
of  the  tube.  The  three  smaller  blood- 
tubes,  the  subnural  and  two  lateral 
nural  tubes,  lie  close  to  the  nerve  cord. 
Each  segment  has  a  transverse  vessel  connecting  the  dorsal 
and  ventral  blood-vessels.     Those  from  the  sixth  to  the  eleventh 


urn 


Fig.  50. — Earthworm 
dissected  to  show  aUment- 
ary  tube,  al.  t.  (From 
Jordan  and  Kellogg, 
"  Animal  Life,"  D.  Apple- 
ton  and  Co.,  Publishers.) 


CH.ETOPODA  67 

segment  are  dilated  and  pulsate  ryhthmically,  hence  are  some- 
times called  hearts.  The  blood  is  red,  the  color  being  due  to 
the  presence  of  hemoglobin  (the  same- substance  which  makes 
our  blood  red)  in  the  liquid  itself,  though  the  blood  contains 
colorless  corpuscles. 

The  nervous  system  consists  of  a  double  cerebral  ganglion 
connected  with  a  double  ventral  chain  of  ganglia  by  a  pair  of 
commissures  which  pass  around  the  esophagus. 

The  earthworm  has  no  eyes,  yet  it  can  distinguish  not  only 
light,  but  the  direction  from  which  it  comes,  and  it  will  crawl 
"  away  from  the  light  of  high  intensity  and  toward  a  light  of  low 
intensity."  This  tendency,  and  the  fact  that  the  moisture  of 
the  skin  would  be  rapidly  evaporated  in  daytime,  and  the  ab- 
sence of  enemies,  induce  the  earthworms  to  feed  at  night. 

The  earthworm  has  no  organs  of  hearing,  but  its  general  sense 
of  touch  is  so  delicate  that  it  detects  the  approach  of  danger 
by  the  jarring  of  the  earth  al)out  its  burrow. 

It  can  distinguish  and  choose  between  different  kinds  of  food, 
so  it  must  have  a  sense  akin  to  smell  or  taste.  It  is  thought  that 
the  "  goblet-shaped  bodies  "  on  the  prostomium  and  on  the 
anterior  segments  are  the  seat  of  this  sense. 

The  body  wall  is  composed  of,  first  (on  the  outside),  the  cuticle, 
then  the  epidermis,  the  dermis,  a  muscular  layer  of  circular 
fillers,  a  layer  of  longitudinal  muscle-fil)ers,  and  underneath  this 
the  coelomic  epithelium  which  lines  the  l)ody  cavity. 

Respiration  takes  place  through  the  thin  moist  skin  which 
is  everywhere  underlaid  liy  a  network  of  blood-vessels.  These 
absorb  the  oxygen  from  the  air  and  give  off  the  carl)onic  acid 
gas  through  the  skin. 

Locomotion. — Each  segment,  except  the  one  at  each  end  of  the 
worm,  is  furnished  with  four  pairs  of  setse,  or  short,  stiff,  chitin- 
ous  bristles.  They  arise  from  the  setigerous  glands  or  sacs 
made  by  the  infolding  of  the  cuticle.  By  special  muscles,  at- 
tached to  the  base  of  each  of  these  sacs,  the  setae  can  be  turned 
in  different  directions.  In  locomotion  the  earthworm  uses 
these  setse  as  levers.  When  it  moves  forward  the  setge  are 
turned  backward  and  stuck  into  the  soil,  the  longitudinal 
muscles  contract,  pulling  the  body  together,  then  the  circular 
muscles  contract,  making  the  body  smaller  and  longer  and  fore- 


G8  BRANCH    ANNULATA 

ing  it  forward,  since  the  setae  prevent  its  moving  backward. 
When  the  earthworm  moves  backward  the  setae  are  directed 
forward,  and  the  same  processes  propel  the  worm  backward. 

Excretion. — In  all  the  segments  of  the  body  except  the  first 
three  and  the  posterior  one  is  a  pair  of  tubular  kidneys  (nephri- 
dia).  Each  begins  in  a  ciliated  funnel — which  opens  into  and 
takes  up  the  waste  from  the  body  cavity — in  the  back  part  of  a 
segment,  and  continues  in  a  long,  much-looped  tube,  which 
opens  externally  by  a  small  excretory  pore  on  the  ventral 
surface  of  the  segment  posterior  to  the  one  in  which  the  funnel- 
shapetl  beginning  is  situated. 

Multiplication. — The  earthworm  is  hermaphroditic,  but 
cross-fertilization  takes  place.  The  lateral  and  dorsal  portions 
of  the  segments  from  the  thirty-secoiid  to  the  thirty-seventh 
are. swollen  and  somewhat  fused  together,  forming  a  sort  of 
girdle  (the  ditellum).  The  glands  of  this  clitellum  secrete  a 
viscid  fluid.  This  secretion  hardens,  upon  exposure  to  the  air, 
and  forms  a  band  or  collar  about  the  clitellum.  This  collar 
moves  forward,  gathers  the  eggs  and  sperms^  as  it  passes  the 
openings,  and  finally  is  slipped  off  over  the  head.^  The  ends  of 
the  collar  now  close  and  it  forms  a  tough  egg-capsule.  The 
egg-capsules  are  hidden  under  stones,  Ijoards,  or  logs,  or  are 
buried  in  the  earth,  especially  about  barnyards  and  compost 
heaps.     "  The  worms  are  about  1  inch  long  when  hatched."' 

They  hiljernate  below  the  frost  line  in  winter. 

Enemies. — The  chief  enemies  are  moles  and  birds.  To 
avoid  the  birds  they  feed  at  night  or  early  morning,  and  some- 
times drag  a  pebble  into  the  mouth  of  the  burrow,  closing  it 
after  them. 

The  marine  worms  {Polyche'ta)  are  dioecious,  and  the  young  undergo  a 
more  or  less  complete  metamorphosis.  The  larva  is  a  trochosphere*  Some 
burrow  in  the  sand;  some  are  free  swimming;  some  secrete  a  mucus  which 
hardens  and  forms  tubes;  others  form  tubes  by  sticking  together  with 
mucus  pieces  of  shell,  sand,  mud,  or  limestone.  Most  of  the  tube-building 
species  are  fixed  to  some  object,  but  a  few  carry  their  tubes  about.  Many 
of  these  marine  worms  live  in  shallow  water,  but  some  have  been  found 
at  a  depth  of  .3000  fathoms. 

•  These  have  been  obtained  from  another  earthworm. 
2  Shipley  and  MacBride,  p.  100. 
'  Colton,  "  Descriptive  Zoology." 
<  See  Glossary 


HIRUDINEA  G9 

The  nereis,  or  sand-worm,  which  is  found  on  the  seashore,  has  a  distinct 
head,  bearing  eyes  antl  tactile  sense  organs,  such  as  tentacles  and  palpi. 
Each  segment  has  a  fleshy  outgrowth,  the  parapodiuitt,  bearing  many  bnsUts. 
"  This  is  the  first  appearance  of  true  appendages,  though  they  are  not 
jointed  to  the  body  nor  in  themselves." 

The  sand-worm  varies  in  color  in  different  stages,  and  the  length  varies 
from  6  inches  to  2  feet. 

It  has  an  eversible  pharynx,  which,  when  infolded,  conceals  two  horny 
jaws.  These  jaws  are  deeply  notched  and  the  ends  are  incurved.  When 
food  is  taken  the  pharynx  is  everted,  the  jaws  thrust  forth,  and  the  prey 
seized  and  swallowed. 

CLASS   II.     GEPHYR'EA 

Class  Gephyr'ea  is  composed  of  oval  or  spindle-shaped  worms, 
which  are  unsegmented  in  the  adult  form.  Setae  are  entirely 
wanting.  The  mouth,  which  is  at  the  anterior  end,  is  either 
surrounded  by  tentacles  or  overhung  by  a  "  proboscis  "  which 
may  be  several  times  the  length  of  the  body. 

These  worms  are  widely  distributed.  They  live  in  both 
deep  and  shallow  water  and,  "  for  the  most  part,  either  in 
natural  rock-fissures  or  in  burrows  which  they  excavate  in  sand 
or  mud  or  in  coral  or  rock." 

CLASS   III.     HIRUDIN^EA 

The  body  of  the  leech  tapers  at  both  ends  and  is  flattened 
dorsoventrally.  It  is  composed  of  many  segments  which  are 
superficially  divided  into  several  rings,  so  that  there  are  not  so 
many  true  segments  as  there  are  surface  rings. 

The  principal  order  of  this  class  contains  the  common  fresh- 
water leech  familiar  to  barefoot  bo}'s.  It  is  a  temporary  para- 
site on  vertebrates. 

The  leech  (Fig.  51)  has  no  setse  nor  appendages,  but  is  pro- 
vided with  two  suckers.  The  one  on  the  posterior  ventral  sur- 
face is  used  for  attachment  in  locomotion,  and  the  other,  which 
surrounds  the  mouth  and  is  not  well  developed,  is  used  in  suck- 
ing the  blood  into  the  large  crop.  In  the  pouches  of  this  crop, 
it  is  said,  enough  blood  can  be  stored  to  last  a  year.  A  narrow 
stomach  and  a  short  intestine  follow  the  pouched  crop.  The 
ccelom  is  considerably  obliterated  by  a  growth  of  muscle  and 
connective  tissue,  called  parenchyma. 

Leeches  are  hermaphroditic.  The  eggs  are  usually  laid 
in  small  packets  or  cocoons,  and  these  are  deposited  in  moist 


70 


BRANCH    ANNULATA 


soil.  The  eggs  are  hatched  in  four  or  five  weeks,  but  it  takes 
them  several  years  to  mature.  Some  leeches  are  said  to  live 
twenty  years. 

Leeches  are  widely  distributed.  Many  of  them  are  in- 
habitants of  fresh  water.  Some  live  in  salt  water,  while  others 
live  in  the  forests  of  many  regions,  especially  those  of  the 

tropics,  where  they  are  the  terror  of  men 

and  beasts. 


dJ 


One  species  ( Hiru^do  sanguisu'ga)  is  a  parasite 
in  the  nasal  passages  of  man.  Another  ( Hcemop'- 
sis  vo^rax)  lives  in  the  pharynx  or  trachea  of  the 
horse,  being  taken  in  with  water  when  small. 
Another  form  {BrancheVlion)  is  a  permanent  ex- 
ternal parasite  on  fishes. 


Distribution. — The  members  of  branch 
Annulata  are  widely  distributed,  the  rep- 
resentatives of  its  many  species  being 
found  from  frigid  to  tropical  regions,  and 
even  in  the  isolated  islands  of  the  sea. 

It  is  known  that  marine  worms  existed 
in  the  Cambrian  Period  by  their  "  tracks 
and  borings  in  the  sand,  which  are  now 
consolidated  into  hard  rocks." 

Economic  Importance. — The  earth" 
worm  swallows  the  soil  which  it  exca- 
vates for  the  sake  of  the  partially  de- 
cayed organic  matter  it  contains,  which 
the  worm  appropriates  to  the  building 
up  of  its  body  tissue.  The  indigestible 
portions  it  deposits  on  the  surface  at 
night  as  coiled  castings.  They  also  feed 
on  fresh  or  decayed  leaves  which  they 
drag  into  their  burrows,  and  sometimes 
upon  young  seedlings  and  tender  roots. 

Darwin,  who  studied  the  earthworm  for 

forty  years,  estimated  that  in  the  tillable 

soil  of  England  there  were  fifty  thousand 

earthworms  to  the  acre,  and  that  they  brought  to  the  surface 

from  10  to  18  tons  of  soil  annually:     In  this  way  the  whole 


Fig.  51. — Section  of 
a  leech:  a,  Anterior 
sucker;  h,  posterior 
sucker;  c,  anus;  d,  d,  d, 
stomach;  a\  esophagus; 
i,  intestine;  .s,  .s,  glands 
of  the  skin.     (Holder.) 


HIRUDINEA  71 

superficial  layer  would  be  enriched  by  passing  through  their 
bodies  in  a  few  years.  Their  burrows  may  extend  vertically  or 
obliquely  for  several  feet  underground,  their  depth  depending 
upon  the  distance  of  the  moist  soil  from  the  surface.  "  They  are 
connected  by  underground  tunnels,  so  that  the  soil  is  thoroughly 
exposed  to  the  chemical  action  of  the  gases  and  acids  of  the  air 
and  water.  "^  Thus  the  action  of  the  earthworm  has  both  a 
chemical  and  a  mechanical  effect  upon  the  soil. 

Leeches  were  formerly  used  very  frequently  by  doctors  when 
bleeding  was  more  often  practised.  They  are  still  sometimes 
thus  used.  They  are  raised  in  France  for  commercial  purposes. 
Swamps  are  stocked  with  them  and  they  are  fed  upon  old  and 
worn  out  farm  animals. 

Important  Biologic  Facts. — This  branch  is  distinguished  from 
all  preceding  groups  by  its  metameric  segmentation.  The 
excretory  system  is  characterized  by  the  peculiar  nephridia. 
There  is  a  well-developed  circulatory  system  and  a  circulating 
fluid  containing  hemoglobin.  In  leeches  eyes  are  found,  while 
the  "  goblet-shaped  organs  "  in  leeches  and  earthworms  are 
thought  to  be  the  seat  of  smell  or  taste.  True  appendages  ap- 
pear in  the  Nereis. 

The  trochosphere  larvae  show  relationship  between  Chaetopoda 
and  the  Turbellaria  and  the  Nemertinia. 

Classification. — 

Class.  Examples. 

I.  Chsetop'oda.  Earthworms,  Sand-worms. 

II.  Gephyr'ea.  Sipunculus. 

III.  Hirudin'ea.  Leeches. 


'Jackson   and  Daugherty,   "Agriculture  Through  the  Laboratory  and 
School  Garden." 


BRANCH   MOLLUS'CA 

These  animals  have  soft,  unsegmented  bodies,  as  contrasted 
with  the  segmented  Arthropoda.  The  body  is  generally  bi- 
laterally symmetric,  but  it  may  be  asymmetric,  as  in  the  snail. 
They  vary  in  size  from  a  fraction  of  an  inch  to  from  2  to  5  feet 
in  length;  and  in  weight  from  a  fraction  of  an  ounce  to  500 
pounds.     The  body  may  be  naked,  as  the  slug;  or  covered 


Fig.  52. — Part  of  a  bunch  of  oysters  from  (ircat  Point  Clear  Reef,  showing 
attachment  of  barnacles  and  mussels.     (Bulletin,  U.  S.  F.  C,  1895.) 


with  a  univalve  shell,  as  the  snail;  or  with  a  bivalve  shell, 
as  in  the  common  mussel;  or  it  may  have  an  internal  horny 
pen,  as  in  the  squid.  The  structure  and  form  of  the  Mollusca 
are  very  various,  and  the  number  of  known  living  and  fossil 
species  exceeds  forty  thousand.  Some  mollusks  are  marine, 
some  are  fresh-water  forms,  and  others  are  terrestrial. 
72 


PELECYPODA  73 

The  circulatory  system  consists  of  a  dorsal  heart  of  one 
ventricle  and  one  or  more  auricles,  enclosed  in  a  pericardium. 
Aortas  carry  the  blood  from  the  ventricle  to  different  parts  of  the 
body,  but  the  blood-vascular  system  is  not  entirely  closed. 

Respiration  is  carried  on  through  the  body  wall  in  a  few 
Mollusca,  Ijut  most  of  them  breathe  through  gills  or  lungs. 

The  nervous  system  is  characterized  by  three  pairs  of  gangha 
which  are  joined  ])y  connective  nerve  cords.  The  cerebral 
ganglia  are  situated  dorsal  to  the  esophagus  and  supply  the 
tentacles  and  eyes.  The  pedal  ganglia  lie  ventral  to  the  mouth 
and  supply  the  foot  and  otocysts.  The  visceral  ganglia,  also 
ventral,  but  farther  back,  supply  the  body,  the  mantle,  and  the 
so-called  "  osphradia,"  or  olfactory  organs.  Some  moUusks 
lack  special  sense  organs. 

Locomotion  is  accomplished  by  the  single  so-called  "  foot," 
a  muscular  plowshare-shaped  thickening  of  the  body. 

Multiplication. — The  Mollusca  may  be  sexually  separate  or 
hermaphroditic. 

This  l^ranch  includes  some  very  valuable  food  animals  for  man, 
as  clams  and  oysters.  Other  examples  are  snails,  slugs,  scallops, 
cuttle-fishes,  squids,  and  fresh-water  mussels. 

CLASS   L     PELECYPODA 

This  class  is  called  by  various  names  by  chfferent  zoologists, 
depending  upon  the  character  taken  for  the  basis  of  classifica- 
tion— as  Aglossa  (without  a  tongue),  Acephala  (without  a 
head),  Bivalva  (of  two  valves),  Pelecyp'oda  (hatchet-footed),^ 
Lamellibranchiata  (leaf-like  gilled).  We  may  then  characterize 
this  class  as  the  hatchetciooted,  headless,  tongueless,  bivalved, 
leaf-like  gilled  mollusks.  Mussels,  clams,  and  oysters  are  com- 
mon examples  of  this  class. 

The  body  is  soft,  unsegmented,  and  is  modified  into  the  large 
"  foot  "  used  for  locomotion.  The  mantle,  a  great  fold  of  skin, 
covers  the  body,  one  lobe  over  each  side.  Between  the  mantle 
lobes  and  the  body  are  the  four  large  leaf-like  gills.  The  labial 
palpi  are  the  small  leaf-like  structures  anterior  to  the  gills,  and 
lead  into  the  mouth.     This  organ  secretes  the  shell. 

Food  consists  of  small  organisms  which  the  water  carries 
into  the  mantle  cavity  and  to  the  ciliated  labial  palpi,  which 


74  BRANCH    MOLLUSCA 

pass  the  food  into  the  mouth.  From  thence  the  food  passes 
into  the  stomach  and  to  the  long  coiled  intestine  which  passes 
through  the  pericardium,  usually  perforates  the  ventricle,  and 
ends  dorsal  to  the  posterior  adductor  muscle. 

The  Pelecypoda  are  sexual  and  sometimes  hermaphroditic. 
There  is  a  metamorphosis,  there  being  usually  a  trochosphere 
stage. 

The  sea  mussel  {My'tilus)  is  an  example  of  this  class.  Great  clusters 
of  this  edible  mussel  are  found  just  below  low-tide  marks.  The  shell  is 
generally  of  a  purple  or  dark  color.  The  long  slender  foot  (Fig.  53)  throws 
out  yellowish  horny  fibers  (the  byssus),  by  which  the  mussel  attaches 


Fig.  53. — Mytilus  edulis:  O,  Mouth;  *S',  labial   palps;    P,  foot;  B,  byssus 
secretion;   Br,   gills;  M,  thickened  edge  of  mantle.     (After  Glaus.) 

itself  to  foreign  objects.  If  food  becomes  scarce  or  conditions  unfavorable, 
it  can  detach  itself  and  slowly  move  to  another  position  by  stretching  out 
the  threads  of  the  byssus  and  attaching  them  ahead  or  above,  and  then 
drawing  itself  up  to  them,  hence  it  is  sometimes  called  the  "  climbing 
mussel." 

Anosmia,  of  the  same  order  as  My^tilus,  is  permanently  fixed. 

The  oyster  {Os'irea)  is  a  member  of  this  class,  whioli  in  adult  life  is  fixed 
to  the  sea  bottom  or  to  some  foreign  object — very  often  the  slid!  of  another 
oyster.  Great  clumps  (see  Fig.  .52,  p.  72)  maybe  thus  ftistenod  together, 
but  their  union  is  not  organic.  Oysters  vary  in  size  from  a  few  inches  to 
2  or  3  feet,  the  largest  being  a  Japanese  species. 

The  shell  of  the  oyster  (Fig.  54)  is  rougher  than  that  of  the  clam,  and  the 
hinge  is  at  the  pointed  end,  which  corresponds  to  the  anterior  end  of  the 
clam.  Its  two  valves  are  not  alike,  but  the  lower  or  left  one  is  much 
larger  and  becomes  deep  enough  to  contain  the  body,  while  the  upper  or 
right  valve  is  flat  and  serves  as  a  lid.     There  is  but  one  adductor  muscle. 


PELECYPODA 


75 


By  its  contraction  the  shell  is  closed.  Its  location  is  changed  from  year  to 
year  as  the  animal  grows.  A  brown  scar  in  the  shell  indicates  where  the 
attachment  has  been.     The  oyster  can  open  its  shell  but  little. 

The  oyster,  since  it  is  fixed,  needs  no  organ  of  locomotion,  and  so  has  no 
foot.  Neither  has  it  any  siphon,  but  the  food-bearing  water  (Fig.  55) 
enters  along  the  curved  border  of  the  shell  and  passes  out  near  the  larger 


Fig.  54. — Shell  of  typical  American  oyster:   1,  Inner  face;  2,  outer  face. 
(Report  U.  S.  Geol.  Survey.) 


end  on  the  straight  side.  A  fresh  supply  of  sea-water  is  necessary  to  fur- 
nish it  with  food  and  oxygen.  If  the  oysters  settle  too  deep  in  the  mud 
or  if  they  are  covered  by  silt  and  sand  in  time  of  storms  they  smother. 

Our  species  of  oysters  {Ostrca  virginiana)  is  bisexual,  while  the  European 
species  are  hermaphroditic. ^     The  reproductive  organ  is  attached  to  the 

1  "Hertwig's  Manual  of  Zoology,"  Kinglsey,  p.  367. 


76 


BRANCH    MOLLUSCA 


large  adductor  muscle.  The  eggs  are  deposited  in  the  water.  They 
are  very  numerous.  It  has  been  estimated  that  one  female  will  produce 
from  9,000,000  to  40,000,000  csKs  in  a  single  season.  The  breeding  ,s(>ason 
is  from  May  to  August.  If  the  eggs  are  not  eaten  by  en(>niics  or  carried 
away  by  currents,  they  .sink  to  the  bottom.  After  a  few  hours  (jf  tlevelop- 
ment  the  larvae  swim  to  the  surface.  Multitudes  of  these  larva;  are  de- 
voured by  surface-living  fishes.  The  larva;  (Fig.  56)  swim  by  means  of 
cilia.     In  a  few  days  the  larva^  or  fry,  as  they  are  called,  sink  to  the  bottom 


Fig.  55. — Food  of  South  Carolina  oyster.  A  few  typical  organisms 
(x  225).  Numbers  1  to  20  are  diatoms.  1-5,  Navicula  (Bory);  6,  N. 
didyma  (K.);  7,  Pinnularia  radiosa  (?)  (K.  S.);  8,  Amphora  sp.  (K.); 
9,  Pleurosigma  fasciola  (E.  S.);  10,  P.  littorale  (S.);  11,  P.  strigosum  (S.); 
12,  Actinocyclus  undulatus  (K.);  13,  Coscinodiscus  radiatus  (E.);  14, 
Cyclotella  rotula  (E.);  15,  Synedra  sp.  (E.);  16,  Diatoma  sp.  (De  C); 
17,  Cymbella  sp.  (Ag.);  18,  Mastogloia  smithii  (Thw.);  19,  Triceratium 
alternans  (Br.  Bai.);  20,  Biddulphia  sp.  (Gr.);  21,  Grain  of  pine  pollen 
(Pinus  rigida);  22,  Foraminifera  (Rotalia);  23,  Zoospore  (Ulva?);  24, 
Spicules.  (After  Bashford  Dean.)  (From  Moore,  U.  S.  Com.  of  Fish 
and  Fisheries.) 

and  attach  themselves  by  the  mantle-fold  to  some  other  oyster  or  to  any 
object  with  which  they  come  in  contact.  It  takes  them  from  three  to 
five  years  to  attain  their  growth.  The  blue  crab  (see  Fig.  74,  p.  101)  is  very 
destructive  to  the  young  oyster. 

One  of  the  greatest  enemies  of  the  oyster  is  the  starfish  (see  p.  55). 
Other  enemies  (Fig.  57)  are  boring  snails,  boring  sponges,  and  internal 
parasites.  One  little  crab  (Pinnothe^res)  which  lives  in  the  mantle  cavity 
seems  to  be  an  example  of  symbiosis  rather  than  a  parasite;  at  least  it  does 
not  appear  to  harm  the  oyster. 


PELECYPODA 


77 


Oysters  abound  in  quiet,  shallow  inlets  of  the  Atlantic  coast  south  of 
Cape  Cod,  and  of  the  Gulf  of  Mexico.  We  have  the  best  oysters  in  the 
world. ^  Our  most  extensive  oyster-beds  are  on  the  Chesapeake  Bay,  at 
Baltimore,  where  they  cover  3000  acres  and  furnish  millions  of  bushels 
yearly.  We  not  only  supply  the  markets  of  our  own  great  cities,  but  send 
large  quantities  to  British  markets.  Oysters  are  found  also  on  the  Pacific 
coast,  on  the  coasts  of  Europe,  of  Australia, 
and  of  Japan. 

The  scallop  {Pecten)  has  an  almost  round, 
fluted  shell  with  a  straight  hinge  without 
teeth,  and  with  unequal  valves,  one  being 
more  nearly  flat  than  the  other.  The  shell  is 
usually  brilliantly  tinted.  The  foot  is  rudi- 
mentary or  altogether  lacking.  The  mantle- 
folds  are  fringed  with  slender  tentacles  and 
the  edge  of  each  lobe  is  set  with  a  row  of 
brilliant  bluish  "  eyes."  When  at  rest  the 
scallop  lies  on  the  sea  bottom  with  its  one  ad- 
ductor muscle  relaxed  and  its  shell  open.  If 
disturbed,  it  quickly  closes  tlie  shell  by  con- 
tracting the  strong  muscle.  This  catches  a 
quantity  of  water  which  is  forcibly  ejected 
through  a  round  aperture  at  either  end  of  the 
straight  flange  of  the  hinge.  The  reaction 
caused  by  forcing  this  water  against  the  great 
body  of  water  outside  propels  the  animal  for- 
ward. Thus,  by  rapidly  opening  and  closing 
its  shell,  it  swims  through  the  water  with 
comparative  ease. 

The   edible   scallop   (Pec^ten  irra'dians)    is 
about   2 J   inches   in   diameter    and   its    color 
varies  from  a  whitish  to  a  reddish  or  purple 
hue.     The  adductor  muscle  is  the  portion  used  by  man  for  food.     This 
scallop  is  found  on  the  Atlantic  coast  south  of  Cape  Cod. 

Pec' ten  max'imus,  found  on  the  coast  of  Great  Britain,  in  water  30  to  40 
fathoms  deep,  is  much  larger.  Its  deeper  shell  was  formerly  used  as  a 
baking-dish  for  oysters,  hence  the  origin  of  the  term  "  scalloped  oysters." 

The  shell  of  another  form  common  in  the  Mediterrnaean  Sea  {Pec'ten 
jacohae'us)  was  worn  as  a  badge  by  the  crusaders  returning  from  the  Holy 
Land. 

The  so-called  pearl-oyster  (M,l,(i<jn'na),  which  does  not  belong  to  the 
oyster  family  at  all,  has  a  shell  whicli  is  more  nearly  circular,  a  little  convex, 
and  sometimes  a  foot  in  diameter.  They  are  found  in  Madagascar, 
Panama,  Ceylon,  East  Indies,  Australia,  South  Sea  islands,  PhiHppines, 
and  the  West  Indies. 

Pearls  are  deposits  of  nacre  formed  about  some  foreign  substance. 
Prof.  Jameson  has  discovered-  by  investigation  upon  the  sea-mussel  that, 
in  their  case,  pearls  are  caused  by  a  parasitic  worm  {Trematode) .  Pearls 
are  collected  by  divers  who  go  down  from  6  to  8  fathoms  for  them.     Hun- 

1  "On  the  coasts  of  Holland,  Belgium,  and  France  far  greater  care  is  taken 
of  their  species  [Os'treaed'tdis)  than  we  take  of  ours  {Os'trea  Virginia' no) , 
but  our  natural  conditions  are  superior  to  theirs." — Linville  and  Kelly,  p.  169. 

-  Linville  and  Kelly's  "  General  Zoology,"  p.  173. 


Fig.  56. — Right  side  of 
embryonic  oyster,  six  days 
old:  m,  Mouth;  s,  vent;  /, 
right  lobe  of  liver;  vl, 
velum.  (Moore,  Bull.  U. 
S.  F.  C,  1897.) 


78 


BRANCH    MOLLUSCA 


dreds  of  vessels  are  engaged  in  this  industry.     Pearls  of  various  shapes  are 
found.     Their  colors  may  be  white,  yellow,  pink,  blue,  red,  green,  or  even 


Fig.  57. — Some  enemies  of  the  oyster:  1,  Drill  (  Uroaalpinx  cinerea): 
2,  mussel  {My'tilus  edulis);  3,  Sabellaria  vulgaris;  4,  periwinkle  (Fulgur 
carica).     (Report-  of  Fish  Commision  for  1897.) 


black.     Round  lustrous  white  ones  are  most  prized  in  Europe  and  America, 
but  those  of  the  yellowish  hue  are  preferred  by  Asiatics., 


79 


Fig.  58. — Section  of  Anodon^la,  showing  the  digestive  tube:  m,  Mouth; 
g,  gullet;  /,  Hver;  s,  stomach;  r,  i,  intestine;  a,  anus;  p,  pericardium;  k, 
kidney;  s.c,  chamber  above  the  gills.     (Furneaux.) 


Fig.  59. — Anodor/ta,  lying  in  one  valve,  with  upper  lobe  of  the  mantle 
removed:  p,  Pericardium;  A-,  kidney;  p.r.,  posterior  retractor  muscle; 
p.a.,  posterior  adductor  muscle;  a.a.,  anterior  adductor  muscle;  a.r.,  anterior 
retractor  muscle;  p.p.,  protractor  pedis  muscle;  a,  anus;  e.s.,  exhalent 
siphon;  i.s.,  inhalent  siphon;  l.m.,  cut  edge  of  the  mantle;  o.g.,  outer  gill- 
plate;  m.l.,  mantle  lobe;  v.g.,  inner  gill-plate;  v,  internal  organs;  /,  foot; 
I. p.,  labial  palps;  Z,  liver;  p.l.,  pallial  line.     (Furneaux.) 

Fresh-water  mussels  (Figs.  58,  59)  or  clams  of  our  ponds,  lakes,  and 
streams  have  firm  leaf-like  gills  and  two  nearly  equal  adductor  muscles. 


80 


BRANCH    MOLLUSCA 


The  siphon  is  incomplete  and  the  pallial  line  is  entire,  that  is,  without 
sinus  or  indentation.  The  foot  is  long  and  compressed.  The  valves  of 
the  shell  are  held  together  by  the  strong  adductor  muscles,  and  opened, 
when  these  relax,  by  the  elastic  spring  or  hinge  ligament.  The  shells  are 
a  dull  black  on  the  outside,  and  pearly  white,  tinted  with  iridescent  hues, 
on  the  inside.  The  shell  of  the  Unio  is  not  so  large  and  strong  as  that  of 
Anodonta,  while  the  latter  genus  has  no  hinged  teeth.  Clams  are  found 
in  ponds  and  large  streams  (which  do  not  dry 
up  in  the  summer),  distributed  along  the  direction 
of  the  strongest  currents  to  insure  food  supply. 
They  are  partly  buried  in  the  mud,  the  open  edge 
of  the  shell  down  and  the  valves  slightly  apart, 
with  the  fleshy  foot  protruding  from  the  anterior 
ventral  margin.  When  disturbed,  the  foot  and 
edges  of  the  mantle-lobes  are  retracted  and  the 
valves  tightly  closed. 

The  shell  is  the  mussel's  principal  means  of 
defense.  It  has  many  enemies  besides  man,  such 
as  the  musk-rat,  raccoon,  mink,  otter,  and  other 
mammals  that  live  in  and  about  the  streams 
where  the  clam  is  found.  Such  animals  as  the 
musk-rat  gnaw  off  the  hinge  ligament  to  get  the 
shell  open. 

The  young  clams  are  carried  in  the  gills,  and 
were  formerly  mistaken  for  parasites,  and  are 
called  glochidea.  They  differ  much  in  shape  from 
the  adult.  The  glochidea,  or  young  clams,  pass 
out  through  the  exhalant  siphon  and  attach  them- 
selves by  hooks  on  the  valves  to  the  gills  or  fins  of 
fishes,  by  which  they  are  protected  from  enemies 
and  kept  supplied  with  fresh  water  until  suffi- 
ciently mature  for  independent  existence,  when 
they  detach  themselves  from  their  host  and  drop 
to  the  bottom  of  the  stream. 

The  giant  clam  (Tridac^na  gi'gas)  of  the  tropics 
has  a  shell  from  2  to  4  feet  long,  which  may 
weigh  from  300  to  .")00  pounds. 

The  soft-shelled  clam  {Mi/'n  arena^ria)  abounds 
in  the  mud  flats  of  the  Atlantic  coast  north  of 
Cape  Cod.  The  young  clams  swim  about  on  the 
surface  of  the  water.  After  the  shell  appears, 
they  sink  to  the  bottom  and  attach  themselves  by 
the  byssus.  When  the  clam  is  about  \  inch  long, 
the  byssus  disappears  and  the  animal  buries  itself 
in  the  mud.  As  it  grows,  it  keeps  enlarging  and 
deepening  its  burrow  until  it  may  extend  from 
8  to  12  inches  below  the  surface  of  the  mud.  The  long  siphons  are  extended 
up  to  within  reach  of  the  sea-water,  whose  currents  bring  to  the  clam  food 
and  air.  The  water  enters  through  the  ventral  siphon,  is  driven  through 
the  gills,  and  finally  passes  out  through  the  excretory  tube,  the  dorsal 
siphon. 

Another  form  much  used  for  food  is  the  "  Quahog  "  {Venus  mercenaria) , 
which  is  characteristic  of  warmer  waters,  and  is  found  from  Cape  Cod  to 
Texas.     It  burrows  a  little  way  below  the  surface,  but  is  often  found  with 


Fig.  m.—Tere'dona- 
vaVis,  removed  from  its 
calcareous  tube,  with 
elongated  siphons. 

(Quatrefages.) 


GASTEROPODA  gl 

its  shell  partly  exposed.  Along  the  Atlantic  coast  people  use  the  Mya 
or  Venus  for  their  "  clam-bakes."  Many  hundred  bushels  are  used  every 
year  for  this  purpose. 

The  razor-shell  clams  have  similar  habits.  They  are  concealed  in 
vertical  holes  in  the  sand  with  the  posterior  end  of  the  shell  uppermost. 
They  have  a  powerful  club-shaped  foot,  and  can  dig  so  rapidly  that  unless 
one  approaches  very  cautiously  they  escape  from  vi(>w.  They  seem  to  be 
sensitive  to  light  and  to  the  "  jar  "  made  by  approaching  footsteps. 

The  borer  {Phobias)  has  its  brittle  but  very  hard  shell  marked  like  a  file, 
with  which  it  bores  into  the  hardest  rocks.  The  united  siphons  are  longer 
than  the  rest  of  the  body.  Some  forms  are  phosphorescent,  emitting 
bluish-white  light. 

The  ship-worm  {Tere^do)  (Fig.  60),  anotherborer,  works  into  wood,  doing 
much  damage  to  ships  in  the  tropics.  The  larva  enters  the  wood  when  it  is 
extremely  small  and  enlarges  the  tunnel  as  it  grows.  The  wood  which 
it  excavates  is  not  used  for  food,  but  is  carried  off  by  the  excretory  siphon. 
Its  food,  which  consists  of  microscopic  organisms,  is  brought  in  by  the 
currents.  The  amount  of  damage  these  borers  do  seems  incredible.  They 
completely  honeycomb  the  hull  of  a  wooden  vessel.  The  best  protection 
against  them  is  the  sheathing  of  the  hull  with  copper.  Palmetto  is  the 
best  resistant  among  woods.  The  ship-worms  caused  the  destruction  of 
a  dam  in  Holland,  threatening  destruction  to  the  country.  Their  dis- 
persal is  wide,  since  they  are  carried  all  over  the  world  in  the  floating  wood 
which  they  attack. 

CLASS   II.     GASTEROP^ODA 

These  are  asymmetric,  usually  univalve  mollusks,  and  the 
head  region  bears  either  one  or  two  pairs  of  tentacles.  As  in 
the  snail  (Fig.  61),  the  eyes  are  borne  either  at  the  bases  or  at  the 


Fig.  61. — A  snail.     (After  Tenney.) 

tips  of  the  tentacles.  The  shorter  tentacles  are  probably  organs 
of  smell.  The  head  contains  the  mouth,  in  which  is  the  tongue, 
covered  by  the  radula,  a  ribbon-like  organ  supplied  with 
chitinous  teeth  and  used  for  rasping  the  food. 

The  mantle  is  not  divided  into  two  parts  as  in  the  mussel,  but 
unites  around  the  neck,  leaving  but  a  small  respiratory  aperture 


82  BRANCH    MOLLUSCA 

into  the  mantle  cavity.  Tlie  foot  is  broad  and  flat  and  is  used 
for  locomotion.  Respiration  is  accomplished  through  the  wall 
of  the  mantle  cavity,  or  by  one  or  two  plume-like  gills  or 
ctenidia  in  the  mantle  cavity.  In  the  air-breathing  forms  there 
may  be  simply  a  pulmonary  sac. 

The  shell  is  a  spiral,  either  flat  or  elongated  (Fig.  62),  and  is 
usually  closed  by  a  flap  or  operculum  (a  horny  plate  growing 
on  the  posterior  portion  of  the  foot)  for  jirotection. 

apex 


whorls  forming  the  spire 


body  whorl 


aperture 


Fig.  62.— A  snail  shell.     (Morse.) 

Some  Gasteropods  are  marine,  some  are  fresh-water  forms, 
and  still  others  are  terrestrial. 

The  limpets  (PateVlidce)  are  uncoiled  forms  with  open  conical  shells. 
They  are  found  adhering  to  rocks  between  tide-marks.  The  foot  acts  as 
a  sucker,  enabling  the  animal  to  resist  a  force  of  a  thousand  limes  its  weight 
when  one  attempts  to  detach  it.  The  common  limpet  {Patella  vulgata)  is 
used  as  food.     It  feeds  upon  seaweeds. 

The  ear-shells  {Haliot'ido'),  found  on  our  western  coast,  have  a  row  of 
perforations  near  the  margin  of  the  shell  through  which  the  tentacles 
pass  to  the  exterior.  The  shells  are  much  used  in  inlaid  work  on  account 
of  their  beautiful  iridescent  color.  They  are  also  used  as  food,  and  the 
shells  are  used  for  making  buttons. 

1  The  cowries  {Cyprce'idee)  have  richly  enameled  shells  with  small  open- 
ings. They  are  beautiful  and  are  sold  for  ornaments,  some  species  being 
much  prized.  A  beautiful  yellow  shell,  an  inch  or  less  long,  which  abounds 
in  the  East  Indies,  is  used  as  money  in  Siam  and  in  parts  of  Africa:  6400 
cowries  are  equal  to  about  36  cents.  The  cowries  are  tropical,  but  a  few 
species  are  found  in  temperate  seas. 


GASTEROPODA  83 

The  helmet-shells  (Cassid'tdce)  are  composed  of  layers  of  different  colored 
material  and  arc  used  for  carving  cameos. 

The  tritons  or  sea  conchs  {Triton'idoe)  have  handsome  shells,  frequently 
more  than  a  foot  in  length.  The  shells  of  one  species  is  used  by  the  South  Sea 
Islanders  as  a  trumpet.  The  Triloii'idoe  have  a  proboscis,  a  well-developed 
siphon,  and  a  short  foot. 

"  The  long,  nearly  cylindric  shells  of  the  Cavolinidae  make  up  much  of 
the  '  pteropod  ooze  '  of  the  deep  seas." 

The  common  periwinkle  (Llltori/na)  (see  Fig.  57,  p.  78)  abounds  on  the 
coast  of  New  England  and  southward,  where  it  is  used  as  food.  It  is 
a  native  of  l-Auope.  It  is  a  vegetable  feeder,  and  is  valuable  in  cleaning 
up  the  seaweeds  from  oyster-beds. 

The  oyster  drill  (  Urosal'pinx  ciuer'ea)  (see  Fig.  57,  p.  78)  bores  a  hole 
through  the  shell  of  the  oyster  and  feeds  upon  its  soft  parts. 

Natica  is  another  drilling  sea-snail  common  on  our  Eastern  coast. 
It  burrows  in  the  sand  for  clams  and  bores  a  hole  with  its  radula,  rotating 
its  own  body  in  the  action. 

The  Nudibranchs. — In  the  Nudibranchs  the  shell  is  entirely  absent  in 
the  adult.  True  ctenidia  are  replaced  as  breathing  organs  by  a  number  of 
secondary  branchiae,  sometimes  simple,  sometimes  branched  processes  or 
leaf-like  tufts,  which  may  be  distributed  over  the  dorsal  surface  (as  in 
E'olis),  or  placed  in  a  row  on  each  side  beneath  the  mantle-flap  (as  in 
PlcitrophyUi'dia).  These  soft  naked  sea-slugs  live  in  shallow  water  near 
the  shore,  crawling  about  and  feeding  upon  the  seaweeds.  Their  protect- 
ive resemblance  is  very  great  on  account  of  both  color  and  form.  They 
move  very  slowly.  This  also  aids  them  in  escaping  the  notice  of  their 
enemies. 

The  land  snails  and  slugs  (Pulmona'ia)  are  air  breathing.  The  air 
enters  the  mantle  cavity  through  a  small  opening  which  is  near  the  right 
side  in  the  dextral  forms  (that  is,  the  spiral  of  the  shell  turns  like  the  hands 
of  a  clock  from  left  to  right),  and  on  the  left  side  in  the  left-handed  {sinis- 
tral) forms. 

Land  snails  ( HelicHdoe)  are  common  in  moist  woods.  They  come  out  at 
night  or  in  cloudy  weather  to  feed  on  succulent  vegetation.  When  they 
are  numerous  they  do  much  damage.  They,  in  common  with  the  pond 
snails,  have  thin  spiral  shells.  They  have  two  pairs  of  tentacles.  The 
upper  and  larger  pair  bears  the  eyes  at  their  tips,  and  the  shorter  pair  is  the 
organ  of  touch.     (See  Fig.  61,  p.  81.) 

The  land  snail  [Helix)  has  no  operculum,  and  when  frost  comes  it  with- 
draws into  its  shell,  fitting  the  opening  to  some  smooth  object,  and  secretes 
a  layer  of  mucus.  This  hardens  upon  drying  and  forms  a  tough  membrane, 
the  epiphragm,  which  closes  the  opening.  In  at  least  one  species  of  Helix 
a  small  hole  is  found  just  below  the  lung  aperture,  through  which  an  ex- 
change of  gases  may  take  place. 

As  a  rule,  snails  lay  their  eggs  in  strings  or  masses,  but  the  land  snails 
bury  their  eggs  singly  or  deposit  them  thus  in  moist  places.  Snails  are 
used  as  food,  being  even  shipped  to  the  United  States  from  Europe. 

Land  slugs  (Limac'idce)  are  naked.  The  shell  is  vestigial  and  con- 
cealed by  the  mantle.  They  have  a  rasping  tongue  like  the  snail's.  The 
giant  yellow  slug  of  California  (Ari'olimax  californica)  reaches  a  length  of 
12  inches. 

The  Pulmonata  are  hermaphroditic.  The  garden  snail  hibernates  by 
coiling  up  in  its  underground  burrow  in  winter. 

Pond  Snails. — The  common  pond  snails  have  but  one  pair  of  tentacles, 
and  the  eyes  are  situated  at  the  bases  of  these.     They  breathe  by  means 


84  BRANCH    MOLLUSCA 

of  a  lung-sac  instead  of  by  gills,  and  must  come  to  the  surface  occasionally 
for  air.  In  genus  Physa  the  spiral  of  the  shell  is  left-handed ;  in  Limnoe'a, 
right-handed,  and  in  Planor^bis  the  shell  is  discoid  or  a  flat  spiral. 

The  eggs  of  genus  Physa  are  deposited  in  gelatinous,  transparent, 
oblong  capsules  of  an  inch  or  less  in  length  attached  to  submerged  sticks 
or  leaves.  Genus  Limme^a  lays  the  eggs  late  in  spring  in  capsules  sur- 
rounded by  a  mass  of  jelly.     The  young  pass  through  a  metamorphosis. 

Still  other  pond  or  river  snails  breathe  by  means  of  gills.  They  live  in 
the  bottom  of  ponds  or  streams  and  are  carnivorous. 

CLASS   m.     CEPHALOPODA 

Class  Cephalop'ocla  (head-footed)  consists  of  such  forms  as  the 
squid,  cuttle-fish,  octopus,  and  nautilus.  They  are  all  marine, 
and,  in  many  respects,  the  most  highly  developed  of  all  mollusks. 
There  is  a  distinct  head,  bearing  a  pair  of  large  well-developed 
eyes,  and  surrounded  by  arms  or  tentacles  which  are  modifica- 
tions of  the  anterior  margins  of  the  foot.^  The  posterior  part  of 
the  foot  is  transformed  into  a  funnel-like  siphon. 

The  body  is  bilaterally  symmetric.  Respiration  is  through 
gills  which  line  the  mantle  cavity.  The  shell  may  be  external, 
as  in  the  nautilus;  or  internal,  as  the  pen  of  the  squid;  or  lacking, 
as  in  the  octopus. 

They  are  usually  carnivorous.  Some  are  solitary,  as  the 
devil-fish;  others,  as  the  squid,  go  in  immense  shoals.  The 
senior  author  has  seen  acres  of  ground  covered  with  the 
catches  of  them  on  the  Pacific  coast. 

The  circulatory  system  is  closed  and  consists  of  a  somewhat 
complete  heart  and  arteries,  capillaries  and  veins. 

The  principal  ganglia  are  grouped  about  the  esophagus. 
The  nervous  system  is  the  most  highly  developed  of  any  of  the 
branch,  consequently  they  are  the  most  intelligent  of  all  mol- 
lusks. 

They  have  the  power  of  quickly  changing  color  to  harmonize 
with  their  environment. 

Cuttlefishes  are  rapid-swimming  Cephalopoda  living  at  a  depth  of  several 
fathoms,  but  sometimes  coming  into  shallower  water.  The  cuttlefish  has  a 
distinct  head  bearing  ten  long  arms,  and  a  pair  of  highly  developed  eyes 
resembling  those  of  a  fish.  The  free  end  of  the  head  bears  the  mouth. 
The  inner  surface  of  each  arm  or  tentacle  is  flat  and  bears  four  longitudinal 
rows  of  suckers.  The  fourth  pair  of  tentacles  is  much  longer  and  more 
slender  than  the  others,  and  the  club-shaped  end  bears  suckers.     The 

1  See  McMurrich,  p.  341. 


CEPHALOPODA 


85 


body  is  covered  by  the  thick  integument  of  the  mantle.     The  internal 
shell  is  calcareous  and  furnishes  the  cuttlebone  used  for  canary  birds. 

Cuttlefishes  are  carnivorous,  feeding  upon  crabs,  clams,  or  fishes. 
They  delight  in  the  daylight  and  in  the  open  sea,  so  they  need  to  be  pro- 
tected from  the  view  of  their  enemies.  For  this  purpose  they  discharge 
an  inky  fluid  to  cloud  the  water  so  as  to  escape  detection.  The  dark- 
colored  secretion  is  carried  in  the  ink-bag  connected  with  the  siphon. 
The  ink  was  used  in  ancient  times  as  a  writing  fluid.  The  sepia  ink  used 
by  artists  in  making  the  sepia  pictures  is  manufactured  from  this  fluid  of  the 
cuttlefish.  The  cuttlefish  is  also  used  as  an  article  of  food  in  the  Old 
World. 


Fig.  63. — Loli'go  vulga'ris.     (After  Verany.) 

Squids  (Fig.  63)  swim  in  schools.  They,  unlike  cuttlefishes,  are  noc- 
turnal. They  are  carnivorous,  feeding  upon  young  fishes.  The  common 
squid  is  a  foot  or  less  in  length.  The  internal  shell  is  a  horny  "  pen  " 
shaped  something  like  a  feather,  which  is  embedded  in  the  dorsal  portion 
of  the  mantle.  By  alternately  taking  water  into  the  mantle  cavity  and 
forcing  it  out,  the  squid  is  driven  rapidly  backward.  It  avoids  detection 
by  its  color  changes  and  by  an  inky  discharge  like  that  of  the  cuttlefishes. 
It  feeds  upon  small  fishes  and  crabs,  which  it  kills  by  biting  with  its  power- 
ful horny  beak.  Its  enemies  are  large  fishes  and  man.  Giant  squids  are 
over  9  feet  long,  with  arms  20  or  30  feet  in  length. 

The  octopus  is  another  member  of  this  class.  It  has  a  short  subsi)herical 
body  without  any  shell.     It  has  eight  sucker-bearing  arms,  with  which  it 


8() 


BRANCH    MOLLUSCA 


Fig.  64. — The  chambered  nautilus. 

'  Year  after  year  beheld  the  silent  t  oil 

That  spread  his  lustrous  coil; 

Still,  as  the  spiral  grew, 
He  left  the  past  year's  dwelhng  for  the  new, 
Stole  with  soft  step  its  shining  archway  through, 

Built  up  its  idle  door. 
Stretched  in  his  last-found  home,  and  knew  the  old  no  more. 


Thanks  for  the  heavenly  message  brought  by  thee. 

Child  of  the  wandering  sea, 

Cast  from  her  lap,  forlorn! 
From  thy  dead  lips  a  clearer  note  is  born 
Than  ever  Triton  blew  from  wreathed  horn! 

While  on  mine  ear  it  rings, 
Through  the  deep  caves  of  thought  I  hear  a  voice  that  sings: 


Build  thee  more  stately  mansions,  O  my  soul, 

As  the  swift  seasons  roll! 

Leave  thy  low-vaulted  past! 
Let  each  new  temple,  nobler  than  the  last, 
Shut  thee  from  heaven  with  a  dome  more  vast, 

Till  thou  at  length  art  free, 
Leaving  thine  outgrown  shell  by  life's  unresting  sea." 

Oliver  Wendell  Holmes. 


CEPHALOPODA  87 

grasps  its  prey.  "  Devil-fishes  "  are  found  in  all  seas.  They  are  gregarious 
when  young,  but  the  adult  is  solitary.  They  creep  about  among  the  rocks 
upon  the  extremities  of  their  arms,  generally  moving  sideways;  or  swim 
rapidly,  either  forward  or  backward.  The  arms  are  somewhat  webbed  at 
the  bases. 

Some  devil-fishes  measure  12  to  15  feet,  others  but  a  few  inches.  They 
are  found  on  our  western  coast  and  in  the  Pacific  islands.  They  are  much 
used  for  food  along  the  Mediterranean  Sea  and  by  the  Chinese  and  Italians 
of  San  Francisco. 

The  Nautilus  (Fig.  64). — This  Cephalopod  has  a  many-chambered, 
spiral,  univulved  shell,  lined  with  pearly  nacre,  hence  is  often  called  the 
"  pearly  nautilus."  It  has  four  gills  instead  of  two.  It  crawls  about 
on  the  sea  bottom  by  means  of  its  many  (about  forty)  small  tentacles. 
It  has  no  suckers.  The  outer  chamber  of  the  shell  is  a  large  compartment 
in  which  the  animal  lives.  As  it  grows,  the  nautilus  ])artitions  off  the  space 
behind  it  and  moves  forward.  A  calcareous  tube  coiitaiiiing  the  si ph uncle, 
a  .slender  tubular  continuation  of  the  body,  extends  through  all  the  septa. 
The  abandoned  compartments  are  filled  with  air. 

The  nautilus  has  a  beak  and  a  rasping  tongue,  like  those  of  the  squid. 
Each  of  its  two  disk-shaped  eyes  is  attached  by  its  convex  side  to  a  short 
thick  stalk.  The  aperture  of  the  eye  is  small,  and  there  is  no  cornea,  no 
iris,  nor  vitreous  humor,  but  simply  the  retina  at  the  base  of  a  disk  or  pit. 
The  nautilus  has  not  the  power  of  changing  its  color,  and  has  no  ink  sac. 

It  lives  in  the  deep  water  in  the  south  Pacific  Ocean,  and  has  been  but 
little  studied.  Many  of  the  species  of  former  ages  are  extinct.  This  is  the 
"  chambered  nautilus,"  immortalized  by  Oliver  Wendell  Holmes. 

Economic  Importance. — Mollusks  are  i)roba])ly  of  more 
direct  use  to  man  than  any  other  invertebrate  branch.  The 
oyster  industry  is  of  vast  importance,  giving  employment  to 
thousands  of  persons  and  bringing  an  annual  income  of  millions 
of  dollars.  Clams  are  also  used  extensively  for  food,  and  peri- 
winkles and  snails  less  extensively.  We  get  also  pearls,  and 
the  mother-of-pearl  for  the  making  of  buttons,  knife-handles, 
and  novelties.  Factories  have  been  established  in  Illinois  and 
Iowa  for  making  liuttons  on  a  large  scale  from  the  fresh-water 
mussel  shell.  This  industry  threatens  to  exterminate  these 
bivalves  unless  means  are  taken  to  protect  and  perpetuate  them. 

The  squid  is  extensively  used  as  bait  in  cod-fishing,  while 
both  the  squid  and  the  cuttlefish  furnish  the  sepia  ink  used  by 
artists.  The  cuttlebone  used  for  canaries  is  another  product 
of  the  cuttlefishes. 

The  ship-worm  does  much  harm  to  dikes,  wharves,  and  piles, 
or  any  wooden  structures  which  have  been  in  water  some  time. 

Important  Biologic  Facts. — The  mollusks  are  the  most  highly 
organized  of  any  of  the  invertebrates  except  the  Arthropoda, 


88 


BRANCH    MOLLUSCA 


and  many  zoologists  place  them  above  the  Arthropoda.  They 
have  a  well-defined  circulatory  system  and  nervous  system  and 
especially  highly  developed  eyes.  They  usually  have  a  metamor- 
phosis, some  of  the  stages  of  which  show  indications  of  affinity 
with  "worms." 
Classification. — 


Class. 
Pel'ecyp'oda. 

Gas'terop'oda. 
Ceph'alop'oda. 


Examples. 
Sea-mussel,     Oysters,     Scallop, 

Fresh-water  mussel. 
Limpets,  Periwinkle,  Snails. 
Cuttlefish,  Octopus,  Nautilus. 


^0  kw.ir5) 


0  42. 


xK-/^^ 


-<>x. 


BRANCH  ARTHROPODA 

Arthrop'oda  may  be  characterized  as  animals  having  bi- 
laterally symmetric  segmented  bodies  with  jointed  appendages 
and  a  chitinous  exoskeleton.  The  segments  of  the  body  are 
not  so  numerous  as  in  the  worms. 

This  branch  includes  a  vast  assemblage  of  animals  which 
are  widely  distributed  over  the  earth.  They  vary  in  habitat, 
being  aquatic,  terrestrial,  subterranean,  aerial,  or  some  com- 
bination of  these. 

Some  are  of  direct  use  in  furnishing  food  for  man,  as  the 
lobster  and  the  bee.  Many  cross-fertilize  plants,  and  are  thus 
of  indirect  use  to  man.  As  common  examples  of  this  branch 
may  be  named  the  lobsters,  crabs,  crayfishes,  spiders,  "  thou- 
san?l-legs,"  and  insects. 

The  digestive  system  is  between  the  circulatory  system  and 
the  nervous  system.  It  is  not  much  coiled,  but  runs  almost 
straight  through  the  body.     (See  Fig.  69.) 

The  circulatory  system  consists  of  a  dorsal  blood-vessel 
open  at  the  anterior  end.  The  blood  is  pumped  forward.  It 
fills  all  the  irregular  spaces  of  the  body,  through  which  it  bathes 
all  the  tissues  and  makes  its  way  back  to  the  dorsal  vessel. 
The  corpuscles  are  colorless  and  ameboid. 

The  respiratory  system  consists  of  gills  in  the  aquatic  forms, 
and  of  air-tul)es  or  trachese  in  the  insects  and  other  terres- 
trial forms. 

The  nervous  system  consists  generally  of  a  double  chain  of 
ganglia,  connected  by  a  doul^le  nerve  cord,  running  along  the 
ventral  side  of  the  body.  (See  Fig.  69,  iV.)  We  should  expect 
to  find  a  pair  of  ganglia  to  each  segment,  but  several  ganglia  may 
be  united,  as  in  the  crayfish,  where  there  are  thirteen  well-marked 
ganglia,  the  three  anterior  ones  uniting  to  form  the  so-called 
brain. 

Multiplication, — The  sexes  are  usually  distinct.  Multiplica- 
tion is  generally  by  fertilized  eggs. 


90  BRANCH    ARTHROPODA 


CLASS   I.     CRUSTA'CEA 


As  examples  of  this  class  may  be  named  crayfishes,  lobsters, 
crabs,  and  "  pill-bugs."  The  body  has  a  limited  number  of 
segments,  about  twenty  in  the  crayfish.  Each  pair  of  append- 
ages is  regarded  as  being  attached  to  a  different  segment. 
The  head  and  thorax  are  united  and  called  cephalothorax. 
The  chitinous  covering,  rendered  hard  by  deposits  of  carbonate 
and  phosphate  of  lime,  is  called  the  carapace. 

Respiration  is  by  gills,  or  branchiae,  though  some  breathe 
through  the  skin. 

The  appendages  are  biramous,  as  seen  in  the  swimmerets  of 
the  crayfish,  A  typically  developed  appendage,  as  the  third 
pair  of  swimmerets,  consists  of  a  main  stalk  (protopod)  and  two 
branches,  the  outer  (exopod)  and  the  inner  (endopod).  Several 
of  the  appendages  lack  some  of  these  parts.  The  student  should 
homologize  the  appendages  and  tell  or  demonstrate  which  ones 
have  missing  parts. 

The  class  Crusta'cea  is  usually  divided  into  two  sub-classes, 
the  En'toinbs'traca  and  the  Mal'acos'traca,  with  several  orders 
under  each. 

Sub-class  Entomostraca  is  composed  of  crustaceans  with  a 
varying  number  of  joints  or  segments.  They  are  usually  small 
or  microscopic.  There  is  a  metamorphosis,  the  first  stage  being 
the  free-swimming  nauplius.  "Parthenogenesis  occurs  in  many 
genera  of  Phyllocardia  and  Ostracoda." — Sedgwick. 

Order  I.  Phyllop'oda  are  small  aquatic  crustaceans  with 
segmented  bodies  and  leaf-like  appendages.  The  brine  shrimp, 
fresh-water  Branchipus,  and  Daphnia  are  examples  of  the 
order.     Daphnia  is  shelled  and  looks  like  a  very  small  clam. 

The  animals  of  this  order  form  an  important  part  of  the 
food  of  fresh-water  fishes.  The  eggs  of  many  species  can 
resist  the  drought,  which  is  a  valuable  means  of  perpetuating 
them  in  small  streams  which  dry  up  in  summer. 

Order  II.  Ostrac'oda  are  small  crustaceans  with  apparently 
unsegmented  bodies  enclosed  in  a  bivalve  shell,  as  the  fresh- 
water Cypris.  The  abdomen  is  rudimentary.  There  are  only 
two  pairs  of  thoracic  appendages,  two  pairs  of  maxillse,  one  pair 
of  mandibles,  one  pair  of  antennae,  and  one  pair  of  antennules. 
The  antennae  and  antennules  are  used  for  locomotion.     The 


CRUSTACEA 


91 


antennules  are  also  provided  with  olfactory  hairs.  Many  of 
this  order  are  marine.  Some,  however,  live  in  brackish  or  in 
fresh  water.  They  live  usually  at  the  bottom  of  their  aquatic 
habitat. 

Order  III.  Copep'oda. — As  examples  may  be  named  para- 
sitic fish  lice  and  the  fresh-water  cyclops.  Respiration  takes 
place  over  the  entire  body  surface. 

The  Cyclops  (Fig.  65)  is  a  small, 
white,  shelless  animal  with  elongated 
segmented  body.  It  has  a  rather  large 
eye  in  the  center  of  its  head. 

Order  IV.  Cirripe'dia  or  Barnacles. 
— These  fixed,  marine,  shelled  crusta- 
ceans are  very  abundant  along  the 
seacoast,  the  rocks  being  covered  with 
them  in  places.  Their  food  consists 
of  small  animals  in  the  water.  One 
may  see  thousands  of  barnacles  snap- 
ping their  food  as  the  waves  and  tides 
dash  over  them. 

Some  forms  attach  themselves  to 
crabs,  moUusks  (Fig.  52),  or  even  to 
whales,  while  others  are  true  external 
parasites,  sucking  the  juices  of  the  ani- 
mals to  which  they  are  attached.  The 
parasitic  forms  are  extremely  degenerate. 

Since  they  have  no  power  of  loco- 
motion by  which  to  escape  their  ene- 
mies, the  barnacles  (Fig.  66)  are  pro- 
tected by  shells  capable  of  "  complete 
closure."     The  body  is  flexed  ventrally 

and  bears  six  pairs  of  cirri,  which  are  used  in  straining  small 
organisms  from  the  water  and  in  carrying  them  to  the  mouth. 
The  mouth  is  surrounded  by  a  pair  of  mandibles  and  two  pairs 
of  maxillae.  Barnacles  are  hermaphroditic,  but  cross-fertiliza- 
tion may  occur.  They  have  a  metamorphosis,  having  first  a 
nauplius  and  then  a  cypris  stage,  the  latter  developing  into 
the  fixed  adult  (Fig.  67).  This  order  furnishes  a  good  illus- 
tration of  the  principle  that  inactivity  leads  to  degeneration. 


Fig.  6.5. — Cyclops:  e, 
Eye;  h,  heart;  eg,  feet; 
/,  eggs.     (Clark.) 


92 


BRANCH    ARTHROPODA 


The  barnacles  (Lepas)  are  found  in  clusters  on  the  bottom  of 
ships  and  often  greatly  impede  their  progress. 


Fig.  66. — Anatomy  of  Lcpas  fascicularis  (Packard):  A,  c,  Six  pairs  of 
legs  or  cirri;  /,  filamentary  appendages;  m,  mouth;  s,  stomach;  h,  openings 
of  the  liver  (l)  into  the  stomach,  which  is  represented  as  laid  open;  i,  in- 
testine; a,  vent;  t,  testis;  v,  vasadeferentia,  one  cut  off;  p,  male  appendage; 
o,  ovary;  e,  adductor  muscle  connecting  the  two  basal  valves;  vs,  scutal 
valve;  re,  carinal  valve;  vt,  tergal  valve.  Enlarged  twice.  B,  1,  Palpus; 
2,  mandibles;  3  and  4,  first  and  second  maxillae.  C,  Nervous  system:  s, 
Brain,  sending  the  optic  nerves  to  the  rudimentary  eye  (e),  each  optic 
nerve  having  an  enlargement  near  the  eye,  i.  e.,  the  ophthalmic  ganglion 
(o);  between  o  and  a  are  the  nerves  which  go  to  the  peduncle;  a,  nerve 
sent  to  the  adductor  scutorum;  ce,  commissure  between  the  supra-  and 
inf ra-esophageal  ganglia  (n) ;  c,  c,  c,  c,  c,  c,  nerves  to  each  of  the  six  feet. 
Enlarged  four  times.     (After  Kingsley.) 


Sub-class  II.  Mal'acos'traca  is  composed  of  crustaceans  of  a 
definite  number  of  segments,  usually  twenty — the  head  of  five 
segments;  the  thorax,  eight;  and  the  abdomen,  seven.     These 


CRUSTACEA 


93 


segments  are  sometimes  so  fused  as  to  puzzle  one  to  distinguish 
twenty  segments,  as  in  the  crayfish,  but  by  regarding  one  pair 
of  appendages  to  each  segment  one  is  able  to  count  the  number 
of  segments  present  in  the  specimen.  There  is  a  number  of 
orders  under  this  sub-class,  but  only  a  few  can  be  mentioned. 

Order  I.  Phyllocar'dia  is  marine.     The  genus  Nebalia,  with 
its  bivalve  carapace,  its  leaf-like  thoracic  feet,  and  biramous 


Fig.  67. — Three  adult  crustaceans  and  their  larvae,  a,  Prawn  {Pe?ieus), 
active  and  free  living;  b,  larva  of  prawn;  c,  Sacculina,  parasite;  d,  larva  of 
SarcHlina;  e,  barnacle  {Lepas),  with  fixed  quiescent  life;  /,  larva  of  barnacle. 
(After  Hackel.)  (From  Jordan  and  Kellogg,  "  Animal  Life,"  D.  Appleton 
ami  Co.,  Publishers.) 


abdominal  appendages,  may  be  taken  as  an  example  of  this 
order. 

Order  II.  Decap'oda. — This  order  consists  of  both  marine 
and  fresh-water  crustaceans.  It  contains  the  best-known  forms 
as  well  as  the  most  useful  ones  to  man,  as  the  crayfish,  lobster, 
shrimp,  prawn  (Fig.  67),  and  crab.     As  the  ordinal  name  sug- 


94 


BRANCH  ARTHROPODA 


Fig.  68. — Aslacus  fluvialilis.  Ventral  or  sternal  views  (nat.  size). 
A,  Male;  B,  female:  a,  Vent;  gg,  opening  of  the  green  gland;  lb,  labrum; 
ml,  metastoma  or  lower  lip;  od,  opening  of  the  oviduct;  vd,  that  of  the  vas 
deferens;  1,  eye-stalk;  2,  antennule;  3,  antenna;  4,  mandible;  8,  second 
maxillipede;  9,  third  or  external  maxillipede;  10,  forceps;  11,  first  leg; 
14,  fourth  leg;  15,  16,  19,  20,  first,  second,  fifth,  and  sixth  abdominal  ap- 
pendages; X,  xi,  xiv,  sterna  of  the  fourth,  fifth,  and  eighth  thoracic  somite; 
xvi,  sternum  of  the  second  abdominal  somite.  In  the  male,  the  9th  to  the 
14th  and  the  16th  to  the  19th  appendages  are  removed  on  the  animal's 
left  side;  in  the  female,  the  antenna  (with  the  exception  of  its  basal  joint) 
and  the  5th  to  the  14th  appendages  on  the  animal's  right  are  removed; 
the  eggs  also  are  shown  attached  to  the  swimmerets  of  the  left  side  of  the 
body.     (Huxley.) 


CRUSTACEA 


95 


gests,  they  have  ten  "  feet."  The  first  pair  is  very  large  and 
armetl  with  large  strong  pincers  or  chelce,  for  defense  or  for 
securing  their  prey.  Their  eyes  are  on  movable  stalks  and 
can  be  withdrawn  under  the  rostrum  or  beak  for  protection. 
The  anterior  thirteen  segments  are  covered  by  a  chitinous 
calcareous  shield  called  the  carapace. 

The  Crayfish  (Fig.  68)  is  the  best  known  inland  example 
of  this  order.  The  twenty  segments  may  be  discerned  by 
counting  one  segment  to  each  pair  of  appendages,  which  are 
arranged  in  the  following  order:  one  pair  of  antennules,  one 
pair  of  antennae,  one  pair  of  mandibles,  two  pairs  of  maxillae, 
three  pairs  of  maxillipeds,  five  pairs  of  legs,  six  pairs  of  swim- 


Fig.  69. — Longitudinal  section  through  Astacus  fluviatilis:  C,  Heart; 
Ac,  cephalic  aorta;  Aa,  abdominal  aorta;  the  sternal  artery  (Sta)  is  given 
off  close  to  its  origin;  Km,  masticatory  stomach;  D,  intestine;  L,  liver; 
T,  testis;  Vd,  vas  deferens;  Go,  genital  opening;  G,  brain;  A^,  ganglionic 
cord;  Sf,  lateral  plate  of  the  caudal  fin;  o,  eye  stalk.     (Huxley.) 


merets,  or  nineteen  pairs  of  appendages  and  a  terminal  segment 
without  appendages,  called  the  telson,  which  contains  the 
vent  or  posterior  opening  of  the  alimentary  tube. 

Its  locomotion  on  four  pairs  of  legs  may  be  forward,  sideways, 
or  backward.  Its  backward  locomotion  by  its  "  tail  fin " 
is  probably  its  best  and  most  rapid  mode  of  locomotion. 

Digestion. — The  food  is  seized  by  the  cheliped  and  may  be 
conveyed  directly  to  the  mouth,  or,  after  being  torn  into  bits, 
may  be  transferred  to  the  pincers  of  the  second  and  third  pairs 
of  legs  and  from  there  to  the  mouth.  The  jaws  move  from  side 
to  side  instead  of  up  and  down.  From  the  mouth  the  food 
passes  into  the  esophagus,  which  is  very  short,  as  the  stomach 
is  in  the  head  (Fig.  69).     In  the  inner  w^alls  of  the  stomach 


96 


BRANCH    ARTHROPODA 


z->-— ;- 


are  three  "  teeth "  or  hard  processes  which  are  controlled 
by  muscles  attached  to  them  and  to  the  carapace.  By  the 
action  of  these  muscles  the  food  is  ground  between  these  teeth, 

which  are  sometimes  called  the 
"  gastric  mill."  In  the  poste- 
rior part  of  the  stomach  there 
is  a  series  of  filaments  or  stiff 
hairs  which  prevent  any  coarse 
or  unground  food  from  passing 
into  the  intestine.  So  the 
stomach  is  a  masticating  rather 
than  a  digestive  organ.  When 
the  food  is  ground  fine  it  passes 
into  the  intestine,  a  straight  tube 
extending  from  the  stomach  to 
the  vent .  The  food  is  acted  upon 
by  the  digestive  fluids  from  the 
glands  which  lie  on  each  side 
of  the  stomach  and  whose  ducts 
enter  just  back  of  the  stomach. 
Digestion  and  absorption  take 
place  in  the  intestine. 

Circulation.— V^hen  the  heart 
(Fig.  71)  contracts  the  blood 
flows  both  forward  and  back- 
ward.   Five  tubes,  or  "  arteries," 


Fig.  70. — Astacus  fluvialilis.  A 
male  specimen,  with  the  roof  of  the 
carapace  and  the  terga  of  the  ab- 
dominal somites  removed  to  show  the 

^ ,,    , viscera    (nat.    size):     aa,    Antennary 

^'''^'  "''^"  artery;  ag,  anterior  gastric  muscles; 

amm,  adductor  muscles  of  the  mandibles;  cs,  cardiac  portiori  of  the  stom- 
ach; gg,  green  glands;  h,  heart;  hg,  hind  gut,  or  large  intestine;  Lr,  liver; 
oa,  ophthalmic  artery;  pg,  posterior  gastric  muscles;  saa,  superior  abdominal 
artery;  t,  testis;  rd,  vas  deferens.     (Huxley.) 


carry  it  forward,  and  two,  backward.  These  "  arteries  "  keep 
dividing  until  they  form  minute  capillaries  with  open  ends. 
The  blood  runs  into  the  irregular  body  spaces,  or  sinuses,  and 


CRUSTACEA 


97 


bathes  the  tissues,  then  goes  into  the  larger  median  ventral 
sinus  below  the  thorax  and  abdomen,  from  which  it  is  conducted 
to  the  gills.  After  being  conveyed  to  the  gill  filaments,  where 
it  is  aerated,  it  is  returned  to  the  heart  through  the  pericardial 
sinus.  The  blood  enters  the  heart,  or  dorsal  vessel,  through 
three  pairs  of  openings,  one  on  each  side,  a  pair  on  the  top,  and 
another  pair  below.  Valves  prevent  the  blood  from  returning 
through  these  openings. 


Fig.  71. — Asiacus  fluriatilis.  The  heart  (x  4).  A,  From  above;  B, 
from  below;  C,  from  the  left  side:  a.a.,  Antennary  artery;  a.c,  alie  cordis, 
or  fibrous  bands  connecting  the  heart  with  the  walls  of  the  pericardial 
sinus;  b,  bulbous  dilatation  at  the  origin  of  the  sternal  artery ;  /i.a.,  hepatic 
artery;  i.a.,  lateral  valvular  apertures;  o.a.,  ophthalmic  artery;  s. a.,  superior 
valvular  apertures;  s.a.a.  superior  abdominal  artery;  st.a.,  sternal  artery, 
in  B  cut  off  close  to  its  origin.     (After  Huxley.) 

Respiration. — The  plume-like  gills  are  attached  to  the 
basal  joints  of  the  legs.  They  are  situated  in  partially 
closed  chambers  between  the  body  wall  and  the  carapace. 
The  water  is  drawn  in  and  out  by  the  "  gill-bailers,"  parts  of 
the  second  maxillae,  in  their  vibration  back  and  forth.  In 
passing  over  the  gills  the  water  is  separated  from  the  blood  by 
an  extremely  thin  membrane.  Through  this  meml)rane  the 
carbon  dioxid  is  thrown  off  and  oxygen  taken  into  the  blood. 

Nervous  System. — Several  ganglia  unite  to  form  the  supra- 


98  BRANCH    ARTHROPODA 

esophageal  ganglion  or  "  brain,"  from  which  a  nerve  cord 
passes  on  each  side,  uniting  below  the  esophagus  in  a  double 
(apparently  single)  ventral  nerve  cord  (Fig.  69),  which  ex- 
tends the  whole  length  of  the  body  and  connects  the  ganglia. 
We  should  expect  to  see  a  ganglion  for  each  segment,  but  there 
are  but  thirteen  ganglia,  some  of  these  being  formed  from  a 
union  of  several.  On  each  side  of  the  esophagus  is  a  large  gang- 
lion; there  are  five  more  ganglia  in  the  thorax  and  six  in  the 
abdomen. 

The  stalked  eyes  are  compound,  being  composed  of  many 
facets.  The  sense  of  touch  is  well  developed.  The  surface 
of  the  body  is  sensitive  and  the  antennae  are  especially  adapted 
for  "  feelers."  The  sense  of  smell  is  thought  to  be  seated  in  the 
hairs  or  setse  on  the  antennules. 

Multiplication. — In  the  spring  the  little  brown  or  black  eggs 
may  be  found  attached  to  the  swimmerets  of  the  female. 
For  some  time  the  young  crayfishes,  by  means  of  hooks  on 
their  claws,  cling  to  the  swimmerets  of  the  mother  for  protec- 
tion. 

Molting. — The  young  crayfish,  which  is  of  much  the  same  ap- 
pearance as  the  adult,  grows  rapidly.  Since  the  shell  is  hard 
the  animal  cannot  enlarge  except  when  it  sheds  its  skin  or  molts, 
which  it  does  periodically.  Even  the  hard  lining  of  the  stomach 
is  cast.  Growth  takes  place  while  the  new  skin  or  shell  is  form- 
ing. 

Restoring  Lost  Parts. — Crayfishes  have  the  power  of  growing 
a  new  leg  to  replace  one  broken  off  by  accident  or  in  a  fight. 
This  accounts  for  the  unequal  size  of  the  chelipeds  in  many 
specimens. 

Habits. — Crayfishes  inhabit  fresh-water  streams  and  ponds, 
lurking  under  stones  or  ledges  in  daytime  and  feeding  at  night. 
When  the  streams  dry  up,  they  dig  holes  in  the  ground  until 
they  reach  water.  These  are  sometimes  many  feet  deep. 
The  clay  dug  out  around  the  hole  is  deposited  in  a  "  chimney." 
In  these  holes  they  probably  live  till  the  next  spring.  Some 
species  do  not  live  in  the  water,  but  burrow  in  the  soft  moist 
earth,  and  one  species  has  been  found  in  the  sea.  Crayfishes 
are  omnivorous,  eating  anything  they  can  get,  but  they  prefer 
worms,  insect  larvae,  and  snails. 


CRUSTACEA'  99 

The  protective  resemblance  is  excellent,  the  colors  varying  from 
a  delicate  pink  or  tan  to  a  dark  green  or  purple. 

Use. — Crayfishes  are  used  by  the  million  in  France,  and  to  a 
limited  extent  in  the  United  States,  for  food.  They  also  furnish 
food  for  fishes.  Raccoons,  muskrats,  and  crows  prey  upon 
them. 

The  lobster  (Fig.  72)  is  marine  and  is  very  much  like  the 
crayfish,  only  much  larger.     Specimens  weighing  twenty-five 


Fig.  72. — A  small  lobster  (dorsal  view)  mounted  on  a  glass  so  as  to  show 
both  dorsal  and  ventral  views.     Students'  work. 

pounds   have   been   captured.     Among   the   invertebrates   the 
lobster  ranks  next  to  the  oyster  as  an  article  of  food  for  man. 

Prawns  and  shrimps  look  like  our  common  crayfish  and  are 
used  to  some  extent  for  food.  They  are  small.  The  common 
prawn  (Palcemone'tes  nnlgn'ris)  is  about  2  inches  long.  It  is 
transparent,  so  that  the  viscera  can  be  seen  through  the  thin 
leathery  carapace. 


100  BRANCH    ARTHROPODA 

Hermit  Crabs  (Fig.  73). — There  are  a  number  of  species  of 
hermit  crabs  which  are  not  true  crabs,  but  are  more  Hke  the 
lobster  and  crayfish.  They  have  the  habit  of  backing  into 
empty  univalve  shells  which  they  carry  about  with  them  and 
into  which  they  may  withdraw  for  protection.  This  habit  has 
resulted  in  a  soft-skinned,  reduced  abdomen,  with  a  spiral 
twist  and  with  no  appendages  except  a  pair  of  hooks  for  hold- 
ing on  to  the  inside  of  the  shell.  The  abdomen  is  always  hitlden 
in  the  shell.  The  head,  thorax,  and  legs  project  when  the 
animal  is  active,  but  are  withdrawn  when  danger  approaches. 


Fig.  73. — Hermit  crab  {Pagii'rus)  in  shell,  with  a  sea-anemone  {Adam'sia 
pallia'ta)  attached  to  the  shell.  (After  Hertwig.)  (From  Jordan  and  Kel- 
logg, "  Animal  Life,"  D.  Appleton  and  Co.,  Publishers.) 

As  it  grows  it  discards  its  shell  and  hunts  a  larger  one.  Some 
of  these  hermit  crabs  have  a  peculiar  commensal  life  with  cer- 
tain sea-anemones  (Fig.  73),  which  they  carry  about  on  their 
shells.  If  the  sea-anemone  becomes  detached  the  crab  hunts 
another  and  places  it  on  its  shell.  The  crab  is  protected  from 
its  enemies  by  the  stinging  threads  of  the  anemone,  also  by 
its  resemblance  to  the  seaweed,  while  the  anemone  is  assured 
of  a  fresh  food  supply  by  being  carried  from  place  to  place  by 
the  crab. 

Crabs  are  other  examples  of  this  order.     The  cephalothorax 


CRUSTACEA 


101 


is  much  broader  than  that  of  the  crayfish,  and  the  abdomen, 
which  is  used  only  to  protect  the  eggs  of  the  female,  is  folded 
under  the  cephalothorax.  They  are  great  scavengers.  Many 
kinds  are  used  as  food.     One  of  the  best  for  this  purpose  is  the 


Fig.  74. — Successive  stages  of  the  molting  of  one  individual  of  the  blue 
crab,  Calli'nectes  sa'pidus.     (G.  Hay,  in  Doc.  580,  Bureau  of  Fisheries.) 


edible  or  "  blue  crab  "  {Callinectes  sapidus),  great  numbers 
of  which  are  caught  along  the  Atlantic  and  Gulf  coasts. 
They  are  best  liked  for  food  just  after  their  molting  (Fig. 
74),  and   are   then    called    "  soft-shelled    crabs."      They   are 


102  BRANCH    ARTHIIOF'ODA 

sometimes  called  "  swimming  crabs  "  because  they  have  the 
last  pair  of  thoracic  legs  flattened  and  paddle-like,  adapted 
for  swinmiing  sideways  quite  rapidly.  They  have  large  sharp 
lateral  spines.  The  strong  chelipeds  are  adapted  for  cutting. 
Each  of  the  other  thoracic  appendages  ends  in  a  point  with  no 
forceps. 

The  little  "fiddler-crab"  lives  in  salt  marshes  along  the  Atlantic  coast. 
The  male  has  one  big  and  one  little  cheliped,  which  he  brandishes  grotesquely 
when  disturbed. 

The  spider  crab  {M acrochei'ra)  of  .Japan  sometimes  measures  from  12  to 
16  feet  from  tip  to  tip  of  le^s,  l)ut  1h<'  body  is  only  a  few  inches — about  a 
foot — in  width,  making  them  very  p(  ruliar  creatures.  At  a  little  distance 
they  look  like  immense  sprawling  si)iders. 

The  little  oyster  crab,  found  so  often  in  our  dish  of  oysters,  does 
no  harm  to  the  body  of  the  oyster,  but  its  life  within  the  shell  insures  its 
food  being  brought  to  it  by  the  currents  of  water  made  by  the  oyster  to 
bring  its  own  food.  This  is  a  case  of  commensalism^  where  there  is  a  decided 
advantage  to  one  animal  and  none,  so  far  as  known,  to  the  other,  yet  the 
intruder  does  no  harm. 

Order  III.  Arthros'traca  comprises  both  marine  and  fresh- 
water forms.     The  first  thoracic  segment,  and  sometimes  the 


Fig.  7.5. — Beach  flea,  Gani'iiiarus  umu'iKs.     (.After  .Smith.) 

second,  is  fused  with  the  head  and  bears  maxillipeds.  The  eyes 
are  usually  sessile.  Gammarus  (Fig.  75)  is  a  fresh-water  form. 
The  Pill-bug. — If  one  searches  under  old  boards  or  logs  he 
will  find  a  small  gray  or  brownish  fourteen-footed  crustacean, 
truly  terrestrial,  with  depressed  body  and  with  gills  on  the  ab- 
dominal appendages.  It  is  called  "  pill-bug  "  from  its  habit 
-    1  See  Jordan  and  Kellogg' s  "  Evolution  and  Animal  Life,"  p.  370. 


ARACHNIDA 


103 


of  rolling  up  into  a  ball  when  surprised.     Its  protective  resem- 
blance is  good.     Its  locomotion  is  Idv  crawling  or  running. 

Some  of  the  marine  Arthrostraca  are  parasitic  on  crabs  and  in 
the  mouths  of  fishes. 


CLASS   II.     ARACH'NIDA 

Arachnids  are  arthro])ods  with  the  head  and  thorax  generally 
fused  into  a  cephalothorax,  bearing  six  pairs  of  appendages. 
The  first  and  second  pairs  are  for  biting.  Then  follow  four 
pairs  of  walking  legs.  There  are  no  antennae,  the  eyes  are  simple, 
and  the  abdomen  is  apodal.^ 

The  abdomen  varies  much.  It  is 
short  in  the  spiders,  long  in  the 
scorpions,  or  is  fused  with  the 
thorax,  forming  a  stout  body  in 
the  mites. 

They  are  usually  oviparous.  How- 
ever, some  scorpions  and  some  mites 
are  viviparous.  They  are  generally 
terrestrial,  but  some  live  in  the 
water.  There  is  no  well-marked 
metamorphosis. 

Order  I.  Scorpion'ida. — Scorpions 
(Fig.  76)  are  arachnitis  with  long 
slender  bodies  ending  in  a  poison 
fang.  The  head  and  thorax  are 
fused  and  bear  several  pairs  of 
jointed  appendages.  The  abdomen 
consists  of  a  broad  anterior  and  a 
narrower  posterior  portion.  There 
are  several  pairs  of  eyes. 

Respiration  is  by  means  of  four  pairs  of  lung-sacs  opening 
on  ventral  side  of  abdomen  from  the  third  to  sixth  segments. 

Food. — They  are  carnivorous,  feeding  upon  spiders  and  in- 
sects, which  they  seize  with  their  pincers  and  sting  to  death. 

Multiplication. — They  are  viviparous.  The  mother  cares 
for  the  young  with  great  solicitude,  carrying  them  about  at- 
tached to  her  body. 

1  See  Glossary. 


Fig.    76'. — Carolina    scor- 
pion {Bu'thus  carolinia' nus) . 


104 


BRANCH    ARTHROPODA 


Size. — One  giant  species  in  Ceylon  is  12  inches  in  length, 
while  American  species  are  about  4  inches  long. 

Habits  and  Distribution. — Scorpions  are  nocturnal.  They 
live  in  tropical,  and  subtropical  countries.  Their  sting  is 
dreaded  by  man,  but  seldom  proves  fatal.  About  twenty  species 
are  found  in  North  America. 

Order  II.  Phalangid'ea. — The  members  of  this  order  look 
like  long-legged  spiders,  with  small  bodies.  Closer  observation 
shows  that  the   abdomen   is   fused   with  the   thorax   and  not 


'  Fig.  77. — Parts  of  a  spider.  1,  Under  part  of  a  spider's  body:  <,  Thorax, 
or  chest,  from  which  the  eight  legs  spring,  and  to  which  the  head  is  united 
in  one  piece;  /,  fangs;  p,  palpi,  or  feelers,  attached  to  the  jaws;  a,  abdomen; 
b,  breathing-slits;  s,  six  spinnerets  with  thread  coming  from  them.  2, 
Front  of  spider's  head:  e,  Eyes;  p,  palpi;  /,  front  legs;  h,  hasp  of  fangs; 
/,  poison-fangs;  j,  outer  jaws.  (From  Holder's  "Zoology,"  American 
'  "she 


Book  Co.,  Publishers.) 


harvest-man  " 
It    frequents 


joined  by  a  pedicel,  as  in  the  spiders.     The 
or  "  daddy-long-legs "    is    a    familiar  exampk 
shady  places  and  feeds  on  small  insects. 

They  are  a  dull  color,  to  fit  their  environment.  So  long  as 
they  remain  motionless  their  protective  resemblance  conceals 
them  very  effectively  from  their  enemies.  The  respiration  is 
Ijy  tracheae. 

Order  III.  Arane'ida,  or  Spiders  (Fig.  77).— These  are 
arachnids  with  unsegmented  abdomen  joined  by  a  pedicel  to 
the  thorax. 


AKACHNIDA 


105 


Appendages. — There  are  two  pairs  of  mouth-parts.  The 
mandibles  or  cheUcerse  are  strong  and  composed  of  two  por- 
tions, the  basal  falx  and  the  sharp-pointed  fang,  in  which  is  a 
small  opening,  the  outlet  of  the  poison  gland.     The  palpi  are 


Fig.  78. — The  bird-spider  (Myg'ale  avicular' ia)  capturing  a  humming-bird. 
(From  Holder's  "Zoology,"  American  Book  Co.,  Publishers.) 


long  and  limli-like  and  are  often  mistaken  for  a  fifth  pair  of 
thoracic  legs.  The  l^asal  joints  are  broad  and  adapted  for 
chewing  the  food.  They  are  called  the  maxillae.  Then  follow 
four  pairs  of  seven-segmented  legs  used  for  locomotion.  The 
spinnerets  on  the  abdomen  are  homologous  to  paired  appendages. 


10()  BRANCH  ARTHKOPODA 

Color. — Almost  all  spiders  are  covered  with  hair.  The  color 
is  partly  in  the  skin  and  partly  in  the  hair.  The  most  common 
colors  are  grays  and  browns,  but  the  colors  are  very  varied,  and 
in  some  species,  as  the  jumping  spider,  they  are  almost  as 
bright  and  gorgeous  as  those  of  butterflies. 

Foods  and  Feeding. — They  are  generally  carnivorous,  sucking 
the  juices  from  their  prey.  Some  spiders  spin  webs,  others  do 
not.  The  spider's  thread  is  composed  of  many  fine  threads, 
each  passing  from  the  body  by  a  separate  tube  and  then  unit- 
ing. The  united  thread  forms  a  cord  finer  than  the  finest  silk 
of  the  silkworm,  hence  it  is  often  used  for  the  "  cross-hairs  " 
of  the  telescope. 

Respiration  is  by  lungs  or  lung-sacs  containing  bookleaf- 
like  plates,  and  by  tracheae. 

Senses. — The  sense  of  sight  is  well  developed,  but  they  seem 
to  be  shortsighted,  seeing  clearly  only  at  a  distance  of  4  or  5 
inches.     The  palpi  are  organs  of  touch. 

Dimoryhism. — Male  spiders  usually  have  longer  legs  and 
smaller  l)odies  than  the  females. 

Sub-order  Tet'rapneu'mones. — These  spiders  have  four  lungs 
and  eight  eyes.  The  most  important  members  of  the  group 
spring  upon  their  prey,  often  catching  mice  and  small  birds 
(Fig.  78).  The  large,  dark,  hairy  spiders  {My g' ale)  found  in 
bunches  of  l)ananas  belong  here.  The  claws  of  the  mandibles 
or  jaws  work  up  and  down  instead  of  from  side  to  side. 

The  trapdoor  spiders  [Cteni'za)  of  the  Southwest  dig  tunnels 
in  the  soil,  line  them  with  silk,  and  cover  them  with  a  close- 
fitting  hinged  lid. 

Sub-order  Dipneu'mones. — The  members  of  this  sub-order 
have  two  lungs  and  a  pair  of  tracheae.  This  group  includes 
the  majority  of  living  spiders. 

The  ground  spiders  {Bras' sidxr)  do  not  spin  a  web,  but  hunt  their  prey 
at  night.  Many  species  make  silken  tubes  in  which  they  lay  their  eggs  or 
hide  when  molting  or  in  winter.  An  eastern  species  lives  in  a  bag  of  silk 
hidden  under  stones. 

The  tube-weavers  iCluhion'idcp). — These  are  also  species  which  spin  no 
web.  In  summer  they  live  in  flat  tubular  nests  on  plants,  sometimes 
in  rolled  leaves.  In  winter  they  live  in  tubular  nests  under  bark  and 
stones. 

The  Funnel  Web  Weavers  {Agalen'idce) . — They  weave  a  concave  sheet 
of  silk  with  a  funnel-like  tube  on  one  side,  and  with  threads  extending  in 


ARACHNIDA  107 

all  direct  icnis  uttachod  to  blades  of  grass  for  support.  In  the  morning  dew 
these  webs  form  a  shimmering  silken  sheet.  The  spider  runs  about  on 
the  upper  surface  of  the  "  sheet  "  and  catches  any  insects  which  light  upon 
it.  The  tube  or  hiding  place  opens  below,  so  that  the  spider  can  escape  if  an 
enemy  appears  upon  the  web.  These  are  long-legged  brown  spiders,  of 
which  the  common  grass  spider  is  a  familiar  example. 

The  "curled-thread  weavers"  are  of  two  kinds,  those  which  spin  regular 
webs  and  those  which  spin  irregular  webs.  The  curled  thread  is  coniijoscd 
of  silk  spun  from  a  special  organ,  the  cribcl'lum,  in  front  of  the  spinnerets. 
It  is  combed  into  shape  by  means  of  stiff  hairs  called  the  calamis'irum  on 
the  metat  arsus  of  the  hind  legs,  as  the  spider  moves  the  hind  legs  rapidly 
back  and  forth. 

Those  spidtrs  which  spin  irregular  curled  threads  (Dictyn'idae)  usually 
make  variously  siiaped  webs  on  fences,  under  stones,  in  rotten  logs,  or  upon 
plants  having  clusters  of  small  flowers  like  the  golden-rod. 

There  are  but  two  genera  of  these  spiders  which  spin  regular  webs 
(Ulobor'idae).  The  "  triangle  spider  "  is  found  all  over  the  country  in  pine 
woods.  Its  web  is  usually  stretched  between  the  twigs  of  a  dead  branch 
of  pine  or  spruce,  and  consists  of  four  plain  radiating  lines  and  a  series  of 
double  cross-lines.  The  spider,  which  rests  near  one  of  the  twigs  from  which 
a  strong  line  is  drawn  to  one  of  the  nth(n-  twigs,  pulls  the  web  tight,  so  that 
the  cross-lines  are  separated  as  far  a>  possible.  When  an  insect  lights 
upon  one  cross-line  the  spider  suddenly  let  s  go,  so  that  the  whole  web  springs 
forward  and  the  insect  becomes  tangletl  up  in  the  other  cross-lines. 

The  cobweb  weavers  {T lurid i'ickv)  build  their  webs,  which  are  ap- 
parently only  a  shapeless  maze  of  threads,  in  the  corners  of  rooms — as  the 
house  spider — or  out  in  the  fields  between  the  leaves  of  bushes,  or  in  the 
fence  corners,  or  among  rocks.  They  are  generally  rather  light  colored, 
small,  and  soft.  They  live  in  their  webs,  hanging  by  their  feet,  with  the 
back  downward.  The  cocoons,  several  of  which  are  made  in  one  season, 
are  soft  and  round  and  hang  in  the  web. 

The  orb  weavers  (Epei'ridnp)  construct  some  of  the  most  wonderful 
homes  built  by  any  animal.  First,  there  is  an  irregular  outer  framework  of 
supporting  lines;  then  there  is  a  number — from  twelve  to  seventy — of  dry 
and  inelastic  lines  radiating  from  the  center.  There  is  an  inner  spiral  of 
these  inelastic  threads  which  begins  at  the  center  and  winds  outward. 
The  rings  of  this  spiral  are  about  as  far  apart  as  the  spider  can  reach. 
Its  use  is  merely  for  support.  The  spider  then  begins  at  the  outermost 
part  of  the  web  and  spins  an  outer  spiral  of  sticky  elastic  threads,  winding 
inward,  the  concentric  circles  being  close  together.  As  it  becomes  neces- 
sary, in  forming  this  outer  spiral,  the  threads  of  the  inner  spiral  are  de- 
stroyed. When  an  insect  touclies  one  of  the  outer  sticky  thnvids  the  thread 
not  only  sticks  to  it,  lint  it  stretches  sothat  the  insect  becomes  tangled  up 
in  the  other  circles,  \\  hicli  is  all  the  easier  to  do  since  the  threads  ai-e  so  close 
together.  Many  species  strengthen  the  web  by  spinning  a  zigzag  ribbon 
across  the  center.  The  making  of  the  entire  web  seems  to  be  done  alto- 
gether by  feeling  and  can  be  done  in  the  dark  as  well  as  in  the  daylight. 

Most  of  the  orb-weaving  species  have  large,  nearly  spheric  abdomens  and 
stout  legs,  sometimes  "  with  humps  and  spines."  These  spiders  are  often 
brightly  colored,  the  colors  of  the  abdomen  being  arranged  in  a  triangular 
or  leaf-shaped  pattern.  Some  species  live  near  the  center  of  the  web, 
hanging  head  downward,  others  hang  back  downward  near  one  edge  of  the 
nest.     In  some  species  the  male  is  smaller  than  the  female. 


108  BRANCH    ARTHROPODA 

The  crab  spiders  ( Thomis'ida;)  are  so-called  because  of  their  short  broad 
form  and  peculiar  habit  of  walking  sidewise  or  backward.  "  They  spin 
no  webs,  but  lie  in  wait  for  their  prey."i  Some  brightly  colored  species 
conceal  themselves  in  flowers.  Their  protective  resemblance  is  so  good 
that  insects  visiting  the  flower  often  light  within  reach  of  the  spider  before 
seeing  it.  They  live  about  plants  and  fences  and  hibernate  in  winter  under 
stones  and  bark. 

The  jumping  spiders  (At'tidce)  have  stout  bodies  and  short  legs,  bright 
colors,  and  conspicuous  eyes.  They  jump  quickly  sidewise  or  backward 
for  a  long  distance.  They  make  no  webs  except  those  in  which  they  hiber- 
nate or  lay  their  eggs. 

The  Running  Spiders  {Lycos' idee). — These  are  the  familiar  hairy  dark- 
colored  si)i(l('is  found  under  stones  and  logs.  They  depend  upon  their 
speed  for  the  capture  of  their  prey  and  run  very  swiftly.  They  resemble 
in  appearance  and  habits  the  so-called  tarantulas  of  the  Southwest,  but  are 
smaller.    The  claws  of  their  mandibles  move  horizontally.     Their  eyes  are 


Fig.  79. — Female  spider  with  young  ones.      (Cooi)cr.) 

of  different  sizes.  Some  of  these  spiders  build  tubular  nests  in  the  ground 
and  Hne  them  with  silk.  They  .sometimes  conceal  the  entrance  with  leaves 
and  sticks.  They  often  drag  the  egg-sac,  a  large  gray  ball,  after  them.  In 
genus  Lyco'sa  the  young  (Fig.  79)  climb  upon  their  mother's  back.  The 
female  of  another  genus,  Dolome'des,  carries  the  egg-sac  "  in  her  mandibles 
until  the  young  are  ready  to  hatch,  when  she  fastens  the  sac  in  a  bush  and 
spins  a  web  of  irregular  thread  about  it  in  which  the  young  remain  for  a 
time." 

Order  Acari'na. — These  arachnids  have  stout  bodies,  there 
being  no  apparent  segments,  the  abdomen  being  miited  with  the 
cephalothorax.  There  is  no  heart  nor  blood-vessels.  The  res- 
l^i  ration  is  performed  by  means  of  tracheae.  They  are  generally 
oviparous;  some  are  viviparous.  Many  are  parasitic  (Fig.  80). 
^  Comstock. 


ARACHNIDA 


109 


The  mouth  parts  are  more  or  less  united  to  form  a  beak.     The 
common  red  mite  sucks  the  juices  of  the  house  plants  which  it 


Fig.  80. — The  chicken  mite  {Dermanys'sus  galli'ncc):  a,  Adult;  />,  tarsus; 
c,  mouth  parts;  d  and  e,  young.  All  much  enlarged.  (Osborn,  U.  S.  Bu- 
reau of  Ent.,  1907). 


^*^^^S3^ 


Fig.  81. — Cattle  tick  (enlarged).     (After  Salmon  and  Stiles.) 

infests.     One  mite  (Dem'odex)  is  parasitic  in  the  hair-follicles  of 
the   dog,   cat,   sheep,   cow,   horse,   and   man.     Another   mite 


no 


BRANCH    ARTHROFODA 


X  (Sarcop'tes  scab'ei)  is  the  itch  mite,  causing  the  disease  called  the 
itch.     Still  another  is  called  the  cheese-mite. 

Ticks  (Ixo'des)  are  parasitic,  blood-sucking  Acarina  which 
attack  man  and  other  mammals.  They  do  not  exceed  a  centi- 
meter in  length,  the  males  being  the  smaller.  The  so-called 
"  Texas  fever  "  of  cattle  is  transferred  by  the  common  cattle 
tick  (Fig.  81). 


L_  

Fig.  82. — Horseshoe  or  king  crab   (slightly  damaged  on  left).       (From 
specimen.) 


Order  IV.  Xiph'osu'ra. — The  Lim'ulus,  or  horseshoe  crab  (Fig. 
82),  is  a  marine  arachnid  living  on  the  bottom  of  the  sea  in 
shallow  water,  creeping  along  in  the  mud  and  sand  and  feeding 


MYRIAPODA 


111 


on  worms.  The  body  has  a  chitinous  covering.  The  cephalo- 
thorax  is  arched  and  bears  the  large  compound  eyes  and  two 
simple  eyes.  The  abdomen  is  almost  hexagonal  and  ends  in  a 
long  caudal  spine.  On  the  ventral  side  of  the  cephalothorax 
are  six  pairs  of  appendages,  used  for  securing  food  and  for 
locomotion.  The  last  pair,  the  operculum,  is  broad  and  leaf- 
like and  covers  the  five  pairs  of  leaf-like  branchial  appendages 
of  the  abdomen.  These  appendages  are  for  respiration.  The 
shape  of  the  body,  its  hard  covering,  marginal  spines,  and  its 
color,  which  harmonizes  with  its  environment,  afford  it  ample 
protection  and  defense. 

There  are  several  other  orders,  but  these  will  suffice  for  our 
purpose  in  the  present  work. 


CLASS  m.     MYRIAPODA 

The  name  indicates  myriad  footed,  hence  the  common  name, 
thousand-legs.  A  myriapod  is  a  worm-like  tracheate  arthropod 
with  a  distinct  head,  a  round  or  flattened 
body  composed  of  many  similar  segments, 
to  each  of  which  is  attached  one  or  two  pairs 
of  appendages.  Myriapods  have  one  pair 
of  mandibles,  one  pair  of  antennae,  and 
numerous  ocelli.  "  A  few  species  are  injur- 
ious to  agriculture,  while  others  are  to  be 
classed  among  our  friends." 

Order  I.  Chilop'oda. — These  are  myria- 
potls  with  the  body  flattened,  with  fifteen 
to  one  hundred  and  seventy  or  more  seg- 
ments, each  bearing  a  single  pair  of  legs, 
and  with  long,  many  jointed  antennae  (Fig. 
83).  The  mouth  parts  are  adapted  for  bit- 
ing. The  opening  of  the  poison  gland  is 
on  the  first  pair  of  legs,  which  are  used 
with  the  mouth  parts.  This  order  includes 
the  centipedes,  as  Liiho'hius,  common  under 
stones.  The  bite  of  the  true  centipede 
(Scolopen'dra)  is  fatal  to  insects  and  to 
other  small  animals,  their  prey,  and  painful  or  even  dangerous 
to  man. 


Fig.  S3. 

pede. 


A  centi- 


112  BRANCH    ARTHROrODA 

Order  11.  Diplop'oda. — These  are  myriapods  with  dorsally 
convex  bodies.  Each  apparent  segment,  beginning  with  the 
fourth  or  fifth,  bears  two  pairs  of  appendages.  There  are  no 
poison  fangs.  The  antennae  are  short  and  few  jointed.  This 
order  includes  the  miUipeds.  An  example  is  lulus.  They 
are  found  under  old  stumps  or  about  rotten  logs.  Their  food 
consists  usually  of  decaying  vegetable  matter,  but  some  forms 


Fig.    84. — Class  collecting  insects. 

feed  upon  growing  plants,  otherwise  they  are  harmless.  They 
have  a  habit  of  rolling  up  into  a  helix-like  coil  when  disturbed. 
They  are  bisexual.  When  hatched  the  young  have  but  three 
pairs  of  legs.  "  By  successive  molts  new  segments  and  append- 
ages are  added  "  until  the  adult  form  is  reached. 

CLASS   IV.     INSEC'TA 

This  class  of  Arthropoda  comprises  a  very  large  number  of 
species.  Three  hundred  thousand,  according  to  Kellogg,  are 
known. 


INSECTA 


113 


Habits  and  Habitat. — Insects  vary  in  their  habitat.  Most 
of  them  are  terrestrial,  some  are  aerial,  others  are  aquatic,  a 
few  even  being  marine,  while  still  others  are   su])terranean. 


iabrom   \^x) 


JpleurTf 


Fig.  85.— External  anatomy 
disjointed:  up,  Uroi)ata<iiiun; 
Kingsley.)      (From  Packard's 


>f  ('(iloptc'mts  spre'tus,  the  iiead  and  thorax 
f,  funnila;  c,  cercus.  (Drawn  bv  J.  S. 
Zoolofry,"  Henry  Holt  &  Co.,  Publishers.) 


Some  are  diurnal,  as  our  common  butterflies;  others  are  noc- 
turnal, as  the  bed-bug;  some,  crepuscular,  as  the  moths.  Some 
are  solitary ;  others  gregarious,  or  social,  as  the  ants  and  bees. 

Plan  of  Structure  (Fig.  85). — The  insect  body  is  divided  into 
three  well-marked  regions — the  head,  thorax,  and  abdomen. 


114 


BRANCH    ARTHROI'ODA 


The  head  bears  the  compound  eyes  and  simple  eyes  (when  they 
are  present),  one  pair  of  antennae,  and  three  pairs  of  mouth 
parts,  which  vary  according  to  the  character  of  their  food. 
Hence  the  mouth  parts  may  be  adapted  for  chewing,  lapping, 
sucking,  or  piercing — "  all  referable  back  to  the  chewing  type. 
These  are,  in  turn,  modified  legs."^ 

The  thorax  has  usually  three  well-marked  segments^ — pro- 
thorax,  mesothorax,  and  metathorax — as  in  the  grasshopper. 
Each  segment  bears  a  pair  of  jointed  ventral  legs.  The  two 
pairs  of  wings,  when  present,  are  outgrowths  of  the  dorsal  por- 


Fig.  Sb 


tion  of  the  meso-  and  metathorax.     Sometimes  there  is  but 
one  pair,  and  in  a  few  cases  none. 

The  abdominal  segments  vary  in  number  and  usually  bear 
no  paired  appendages  except,  sometimes,  on  the  terminal  seg- 
ments. 

Covering. — Over  the  greater  portion  of  the  surface  of  the  body 
the  cuticle  or  external  layer  of  the  skin  is  made  firm  and  horny 
by  a  substance  called  chitin.  This  forms  an  exoskeleton  for  the 
protection  of  the  soft  parts  within,  and,  by  its  rough  interior 
surface,  provides  points  of  attachment  for  the  numerous  small 
but  strong  muscles. 

1  Kingsley's  Hertwig,  "  A  Manual  of  Zoology." 


INSECTA 


115 


Those  portions  of  the  cuticle  which  do  not  contain  much 
chitin  are  easily  bent,  thus  permitting  motion  between  the 
segments  of  the  body  and  of  the  appendages. 

All  insects  have  hairs  scattered  more  or  less  abundantly  or 
regularly  over  the  body.  In  Lepidoptera  the  hairs  are  modified 
into  scales,  as  is  shown  on  the  wings  of  a  butterfly,  where  "  all 
the  gradations  from  hair  to  scale  can  be  found  by  going  from 
the  base  out  to  the  distal  area  of  the  wing."^ 

Self-defense  (Fig.  86)  is  by  various  methods  and  organs, 
which  will  suggest  themselves  to  the  student  from  his  past 
experience.     When  insects   cannot  sting  or  bite,   they  often 


Fig.  87. — Al'aus  ocula'tus  and  larva,  showing  eye-spots.     (After  Harris.) 


defend  themselves  by  threatening  attitudes.  In  some  cases 
one  is  reminded,  at  first  sight,  of  a  snake's  head,  and  retreats 
in  terror.  The  "  eye-spots  "  (Fig.  87)  and  "  horns  "  (Fig.  88) 
on  many  insects  are  probably  for  the  purpose  of  terrifying  ap- 
pearance. 

Protective  Coloration. — Insects  attract  attention  by  the 
variety  and  intensity  of  their  colors  and  by  their  numerous, 
interesting,  and  often  l)eautiful  color-patterns.  Many  natural- 
ists believe,  and  have  confirmed  their  opinions  by  observation 
and  experiment,  that  the  variety  of  color  and  color-patterns  of 

1  Kellogg,  p.  592. 


116  BRANCH    ARTHROPODA 

insects  and  of  other  animals  is  indirectly  due  to  two  causes: 
first,  the  advantages  given  to  the  individual  or  species  in  the 
struggle  for  existence  by  these  specific  colors  and  color-patterns, 
which — as  in  the  case  of  the  gray  moth  on  the  tree-trunk  or 
the  katy-did  among  the  green  leaves — helps  to  conceal  them 


Fig.  SS.— Larva  of  rciial  walnut  iiidtli  {('itluro'nui  nija'Us)  cxtcmled  (two- 
thirda  nal.  sizt_0-      (rhotographud  from  life.) 

from  their  enemies  by  affording  protective  resemblance,  or — as 
in  the  case  of  the  bumble-bee  or  the  milkweed  butterfly — to 
warn  the  enemy  of  the  danger  of  sting  or  of  the  disagreeable  odor 
and  taste.     The  advantage  gained  is  easy  to  be  seen  in  each 


Fig.  89. — Pupa  of  regal  walnut  moth  (three-quarters  nat.  .size).       (From 
Ufe.) 

case.  They  believe  that  these  particular  color-patterns  are 
due,  in  the  second  place,  to  gradual  development  ''  through 
natural  selection  of  naturally  occurring,  advantageous  varia- 
tions." 

The  direct  cause  of  color  may  be  chemical,  depending  on  the 


INSECTA 


117 


chemical  composition;  or  physical,  depending  upon  the  structural 
or  physical  make-up;  or  it  may  be  due  to  a  combination  of 
both  of  these.  In  the  most  highly  colored  group  of  insects, 
the  Lepidoptera,  the  color  is  due  to  the  chemical  substances 
(pigment  granules),  to  the   structural  character  of  the  scale 


Fig.  90. — The  protective   resemblance  of  the  leaf-butterfly  (KaVliyna). 
(Holder,  after  Wallace.) 


walls  (strise),  and  to  the  overlapping  (lamination)  of  the  scales 
laterally,  as  well  as  to  the  overlapping  of  the  tips  of  the  scales 
in  one  row  over  the  bases  of  the  scales  of  another  row. 

"  The  blacks,  browns,  yellows,  and  dull  reds  of  butterflies  and 
moths  are  produced  chiefly  by  the  pigments  (chemical  colors), 
while  the  brilliant  metallic  colors,  the  iridescent  blues  and 


118 


BRANCH    ARTHROPODA 


greens,  .  .  .  are  due  to  the  structural  or  physical  make-up  of  the 
scale  covering."^ 

Variable  Protective  Resemblance. — Often  the  different  indi- 
viduals of  the  same  species  are  of  slightly  different  colors,  the 
colors  varying  to  harmonize  with  the  particular  environment 
of  the  individual  during  its  development,  being  fixed  in  the 
adult. 

Special  protective  resemblance  (Fig.  90)  is  illustrated  by 
Kallima,  which  resembles  a  dead  leaf,  and  Phyllium,  resembling 
a  green  leaf  (Fig.  91),  and,  more  commonly,  by  the  measuring- 
worm,  as  it  holds  the  body  out  stiff,  imitating  a  short  or  broken 
twig.  Thus  in  many  cases  "  the  insect's  appearance  simulates 
in  more  or  less  nearly  exact  ways  some  par- 
ticular part  of  the  habitual  environment." 

JVarning  colors  are  possessed  by  many 
insects  having  a  special  organ  of  defense 
• — as  the  sting  of  that  wonderful  little 
stimulator,  the  hornet — or  a  disagreeable 
taste  or  odor,  as  that  of  the  milkweed  or 
"  monarch  "  loutterfly  {Anosia  plexippus) 
(Fig.  92,  a).  Other  examples  of  insects 
having  conspicuous  or  warning  colors  are 
the  black  and  yellow  wasps  and  bees,  the 
lady-bird  beetle,  and  the  swallow-tail  but- 
terflies. Many  others  might  be  mentioned. 
Since  the  bodies  of  insects  are  soft,  one 
can  easily  see  why  these  conspicuous  colors 
are  of  natural  advantage.  A  single  stroke 
of  the  beak  of  a  bird  might  prove  fatal 
to  any  of  them.  The  bird  must  learn  by 
experience  that  the  insect  is  armed  or  distasteful,  but  if  the 
insect  is  conspicuously  colored,  it  will  be  noticeable  and  easily 
remembered,  so  that  the  bird  will  not  attack  another  of  this 
brightly  colored  kind.  Hence  the  species  will  be  perpetuated 
and  the  characteristic  colors  handed  down  to  the  next  genera- 
tion, or,  in  other  words,  "  preserved  and  accumulated  by  natural 
selection." 

Alluring  or  directing  colors  or  forms  may  be  found  among  in- 
'  Kellogg. 


Fig.  9i.—Phyl'- 
lium  siccifo'lium 
feeds  on  leaves,  and 
mimics  fresh  leaves. 
(Holder.) 


INSECTA 


119 


sects,  according  to  Poulton.  The  apical  portion  of  the  fore- 
wing  and  the  hind  portion  of  the  posterior  wing  are  especially 
marked  with  borders  or  eye-like  spots,  and  are  often  prolonged, 
as  in  the  swallow-tail  butterfly,  into  antennae-like  processes  or 
tails.  These,  resembling  the  head  with  eyes  and  antennae, 
direct  the  stroke  of  the  enemy  to  this  part.  The  insect  thus 
escapes  with  the  loss  of  the  tip  or  a  scrap  of  the  wing,  thus  saving 
its  head  or  its  soft  body. 


Fig.  92. — a,  Monarch  butterfly (^no'sia  plexip'pus),  distasteful  to  birds. 
b,  Viceroy  (Basilar'chia  archip'pus),  which  mimics  it.  (From  Kellogg's 
''Zoology,"  Henry  Holt  &  Co.,  Publishers.) 

Mimicry. — The  viceroy  butterfly  (Fig.  92,  h)  imitates,  uncon- 
sciously, of  course,  the  common  "  monarch "  or  milkweed 
butterfly,  since  the  latter  is  seldom  eaten  by  birds,  owing  to  a 
disagreeable  taste  or  odor.  Many  bees  are  mimicked  by  flies, 
and  distasteful  beetles  by  other  beetles. 

Muscular  System  and  Locomotion. — Locomotion  may  be  in 
any  one  or  all  of  three  ways — running,  jumping,  or  flying.    The 


120  BRANCH    ARTHROPODA 

muscular  system  varies  widely  in  the  different  forms.  In  the 
caterpillars  there  is  a  "  sirhple  worm-like  arrangement  of 
segmentally  disposed  longitudinal  and  ring  muscles,"  while  in 
the  more  active  forms,  as  flies  and  bees,  the  muscular  system  is 
complicated.  The  muscles  are  composed  of  fine,  cross-striated 
fibers,  forming  masses  of  various  sizes,  and  are  attached  to  the 
rough  inner  surface  of  the  exoskelton.  The  muscles  are  trans- 
parent and  have  great  contractile  power. 

Digestive  System. — The  alimentary  tube  (Fig.  93),  which  may 
be  coiled  much  or  little,  varies  greatly.     It  is  about  the  length 


Fig.  93. — Internal  anatomy  of  Calopte'nus  fe'mur-ru'brum:  at,  Antenna 
and  nerve  leading  to  it  from  the  "  brain  "  or  supra-osophageal  ganglion 
(sp);  oc,  ocelli,  anterior  and  vertical  ones,  with  ocellar  nerves  Icadhig  to 
them  from  the  "  brain  ";  ae,  esophagus;  m,  mouth;  lb,  labium  or  under  lip; 
if,  infra-esophageal  ganglion,  sending  three  pairs  of  nerves  to  the  man- 
dibles, maxillee,  and  labium  respectively  (not  clearly  shown  in  the  engrav- 
ing); sm,  sympathetic  or  vagus  nerve,  starting  from  a  ganglion  resting 
above  the  esophagus,  and  connecting  with  another  ganglion  (.sgr)  near  the 
hinder  end  of  the  crop;  sal,  salivary  glands  (the  termination  of  the  salivary 
duct  not  clearly  shown  by  the  engraver);  nv,  nervous  cord  and  ganglia; 
ov,  ovary;  ur,  urinary  tubes  (cut  off,  leaving  the  stumps);  ovt,  oviduct; 
sb,  sebaceous  gland;  be,  bursa  copulatrix;  ovt',  site  of  opening  of  the  oviduct 
(the  left  oviduct  cut  away);  1-10,  abdominal  segments.  All  other  organs 
labeled  in  full.  (Drawn  from  his  original  dissections  by  Mr.  Edward 
Burgess.)     (From  Packard's  "Zoology,"  Henry  Holt  &  Co.,  Publishers.) 

of  the  body  in  carnivorous  forms,  and  longer  in  the  herbivorous 
insects.  It  consists  of  a  mouth,  esophagus,  crop,  gizzard  (the 
chitinous  lining  of  which  is  toothed  for  grinding  the  food),  a 
digestive  stomach,  and  an  intestine.  There  may  be  one  or  two 
pairs  of  salivary  glands,  and  usually  two  or  more  pairs  of 
gastric  caeca  containing  glands  supposed  to  supply  digestive 
fluids.  The  intestine  usually  consists  of  a  small  intestine  and  a 
large  intestine,  the  two  regions  of  the  latter  being  the  colon  and 
the  rectum.  The  Malphighian  tubules,  fine  tubes  connected 
with  the  intestine  at  the  beginning  of  the  rectum,  take  the  place 


'INSECTA  121 

of  kidneys.  There  is  no  liver.  The  entire  viscera  are  en- 
veloped in  the  "  lat  body."  The  anal  opening  is  in  the  last 
segment  of  the  abdomen. 

Insects  feed  upon  the  juices,  leaves,  or  even  the  wood  of 
plants,  or  are  parasitic  or  predaceous  upon  various  forms  of 
insects,  and  upon  other  animals  as  well.  Some  live  upon  de- 
caying organic  matter. 


Fig.  94.— Ideal  transverse  section  of  an  insect:  h,  Dorsal  vessel;  i, 
intestine;  n,  ventral  nerve-cord;  f,f,  stigmata  leading  into  the  branched 
tracheal  tubes;  w,  iv,  wings;  a,  coxa  of  one  leg;  b,  trochanter;  c,  femur; 
d,  tibia;  e,  tarsus.     (After  Packard.) 

The  circulatory  organs  are  extremely  primitive  in  character. 
The  heart  or  dorsal  vessel  extends  through  the  abdomen  just 
underneath  the  dorsal  surface.  It  is  partially  divided  by  valves 
into  chambers,  the  number  of  which  varies.  The  anterior 
chamber  extends  into  or  near  the  head  and  is  sometimes  called 
the  aorta.  The  heart  chambers  pulsate  rhythmically,  from  the 
posterior  one  forward,  and  force  the  blood  out  into  the  body 
cavity.  There  are  no  veins  or  arteries,  so  it  flows  through  the 
sinuses  or  open  spaces  between  the  organs,  bathing  the  tissues, 
and  finally  bathing  the  walls  of  the  alimentary  tube,  where  it 


122  BRANCH    ARTHROPODA 

takes  up  the  food  supply  and  then  re-enters  the  heart  through 
the  side  openings.  It  does  not  supply  the  tissues  with  oxygen, 
since  it  receives  only  enough  for  its  own  use. 

Respiration  is  carried  on  by  a  series  of  air-tubes  called 
tracheae.  These  tubes  are  interbranching  and  penetrate  to 
every  portion  of  the  body.  The  air  enters  them  through  a 
pair  of  stigmata  or  pores,  one  on  either  side  of  each  segment. 
The  functions  of  these  tracheae  are  to  take  up  oxygen  from  the 
air  and  to  distribute  it  to  the  tissues  of  the  body,  since  this  is 
not  done  by  the  circulation  of  the  blood,  and  to  collect  and  carry 
off  the  carbon  dioxid. 

Insects  which  live  in  water  either  come  up  to  the  surface  to 
breathe  and,  in  some  cases,  to  take  down  a  supply  of  air  held 
on  the  outside  of  the  body  by  a  fine  pubescence,  or  they  are 
provided  with  tracheal  gills  which  will  enable  them  to  breathe 
air  mixed  with  water.  Gilled  insects,  of  course,  do  not  have  to 
come  to  the  surface  to  breathe. 

The  Nervous  System. — Besides  the  central  or  ventral  (Fig. 
93)  nervous  system  (see  Branch  Arthropoda),  insects  have 
a  small  and  varying  sympathetic  nervous  system  (Fig.  93), 
consisting  of  a  few  small  ganglia  sending  nerves  to  the  automatic- 
acting  visceral  organs.  Commissures  connect  the  sympathetic 
system  with  the  brain  just  at  the  origin  of  the  subesophageal 
commissures. 

Touch. — The  sense  of  touch  is  located  in  the  "  hairs  "  dis- 
tributed over  the  various  parts  of  the  body,  but  most  numerous 
on  the  feelers. 

Taste  is  located  on  small  papillae  or  in  ])its  on  the  mouth- 
parts,  particularly  on  the  tips  of  the  palpi  and  on  the  upper  wall 
of  the  mouth. 

Smell  is  probaljly  the  most  used  sense  of  insects.  The 
organs  of  this  sense  are  minute  papillae  and  "  microscopic  pits  " 
on  the  antennae  and  mouth  ]:)arts.  It  has  been  proved  that 
most  insects  find  their  food  l)y  this  sense.  "  It  is  believed  that 
ants  find  their  way  back  to  their  nests  by  the  sense  of  smell  and 
that  they  can  recognize  by  scent,  among  hundreds  of  individuals 
taken  from  various  communities,  members  of  their  own  com- 
munity."' 

'  Kellogg's  "  American  Insects." 


INSECTA  123 

Hearing. — Many  insects  have  sound-producing  organs  and 
auditory  organs;  and  it  has  been  proved  by  experiment  that  they 
hear.  The  ear  of  the  grasshopper  or  locust,  a  small  tympanic 
membrane,  is  situated  at  the  anterior  end  of  the  abdomen,  while 
that  of  the  katy-did  and  cricket  (Fig.  95)  is  situated  on  the  tibia 
of  the  fore-leg.  There  is  a  special  auditory  ganglion.  The 
mosquito  has  its  auditory  organs  in  the  antennae  in  the  seg- 
ments next  to  the  basal  ones,  through  which  the  sound  or  vibra- 
tions are  carried  by  many  fine  auditory  hairs,  and  from  which  the 
auditory  nerves  lead  to  the  "brain."  It  is  thought  that  the 
male  mosquito  finds  his  mate  by  her  song. 

Sight. — Insects  usually  have  both  simple  and  compound 
eyes,  though  either  kind  may  be  found  alone;  and  a  few  in- 
sects are  blind  by  degeneration.  The  ocelli,  or  simple  eyes, 
are  usually  three  in  number  and  form  a  little  triangle  on  the 


Fig.  95. — The  front  leg  of  the  cricket  enlarged,  showing  the  ear  at  a. 

top  of  the  head.  Each  of  them  is  supplied  with  a  special  nerve 
from  the  "  brain."  It  is  thought  that  the  ocelli  can  do  little 
more  than  distinguish  light  from  darkness  and  that  their  range 
of  vision  is  restricted  to  an  inch  or  two  in  front  of  the  head. 
The  compound  eyes,  two  in  number  (see  Fig.  84),  are  usually 
large  and  conspicuous,  often  composing  more  than  two-thirds 
of  the  entire  head.  Each  compound  eye  presents  from  twenty 
to  several  thousand  polygonal  facets,  or  windows,  which,  alto- 
gether, form  the  cornea.  It  is  thought  that  the  range  of  vision 
of  the  compound  eyes  is  two  or  three  yards.  The  larger  the 
eyes,  the  wider  will  be  the  range  of  vision,  while  the  smaller 
and  more  numerous  the  facets,  the  sharper  and  more  distinct 
will  be  the  image.  Experiment  and  study  of  the  structure  of  the 
eye,  says  Kellogg,  "  indicate  that,  at  best,  the  sight  of  insects 
cannot  be  exact  or  of  much  range." 


124  BRANCH    ARTHROPODA 

The  psychology  of  insects  is  a  very  interesting  study.  Whether 
the  activities  of  insects  are  due  to  reflex  action,  instinct,  or 
intelhgence  can  be  better  determined  when  studying  the  various 
species,  but  one  will  surely  find  that  insects,  as  well  as  being  the 
most  numerous  and  various,  are  also  the  most  interesting  and 
wonderful  of  all  the  classes  of  invertebrates. 

Multiplication  is  by  eggs,  of  which  many  are  deposited  in 
various  places.  Some  are  placed  on  or  in  another  animal's 
body,  others  on  leaves  or  stems  of  plants,  which  serve  as  food 
for  the  young.  However,  some  insects,  as  the  Aphides,  show 
parthenogenesis,  i.  e.,  they  are  supposed  to  produce  young 
from  unfertilized  eggs. 

Metamorphosis. — Insects  pass  through  a  more  or  less  com- 
plete series  of  changes,  called  metamorphosis.  The  larvae, 
whose  business  it  is  to  feed  and  grow,  are  called  by  various  names, 
as  caterpillars,  grubs,  nymphs,  and  maggots.  Since  the  larvae 
are  wingless  they  are  placed  in  different  relations  to  their 
environment  from  those  of  the  adult,  and  hence  often  have 
special  larval  organs.  The  larval  stage  is  followed  by  a  quiet 
stage  called  the  pupa  (Fig.  89).  In  this  condition  many  in- 
sects pass  the  winter  and  come  forth  in  the  spring  as  adults 
or  imagoes,  the  reproductive  stage.  Others  remain  in  the 
pupa  stage  but  a  few  weeks,  thus  giving  time  for  two  or  more 
broods  in  a  season.  "Parthenogenesis  occurs  in  Hymenoptera 
and  Hemiptera."— Sedgwick.    ' 

Parasitism  is  common  in  insects.  Parasites  may  be  ex- 
ternal or  internal.  The  natural  consequence  of  a  parasitic  hfe 
is  degeneration,  as  is  seen  in  lice  and  fleas,  whose  ancestors  were 
winged  insects. 

Environmental  Influences. — Insects  are  affected  by  tempera- 
ture. They  become  active  with  the  rise  of  temperature  in  the 
spring,  and  some  become  dormant  or  hibernate  as  the  tempera- 
ture declines  in  fall  and  early  winter.  Most  of  them  die  with 
the  advent  of  frost.  The  direction  and  velocity  of  the  wind 
is  a  factor  in  insect  life,  especially  in  its  distribution. 

The  amount  of  precipitation  will  influence  the  amount 
and  kind  of  vegetation,  which  determines  to  a  large  extent  the 
number  and  kind  of  insects.  Certain  kinds  of  precipitation, 
as  hail,  for  example,  or  floods,  would  destroy  large  numbers  of 
insects.     Any  environmental  factor  would  increase  or  decrease 


INSECTA 


125 


the  activity,  food,  enemies,  dispersal,  migration,  mentality,  or 
other  phenomena  connected  with  animal  life. 

Geologic  Distribution. — Insects  of  some  kind  have  existed 
for  a  long  time  geologically,  insect  remains  being  found  in  the 
lower  and  upper  Silurian. 

Economic  Importance. — Insects  devour  our  crops,  carry  dis- 
ease, annoy  us  when  awake  and  prey  upon  us  when  we  sleep, 
injure  or  destroy  our  stock,  infest  our  orchards,  and  in  some 
countries  the  white  ants  do  much  damage  to  dwellings.  The 
damage  to  our  American  crops  has  been  estimated  at  the  enor- 
mous sum  of  $700,000,000  in  one  year.  But  when  we  remember 
that  insects  are  also  dangerous 
to  health  and  life,  how  much 
more  is  the  number  of  injuri- 
ous insects  to  be  deprecated. 
Kellogg  says,  "  Mosquitos  help 
to  propagate  and  are  almost 
certainly  the  exclusive  dis- 
seminating agents  of  malaria, 
yellow  fever,"  and  other  dis- 
eases; *'  house-flies  aid  in 
spreading  typhoid  fever  and 
other  diseases;  fleas  are  agents 
in  distributing  the  germs  of 
the  bubonic  plague."  Howard 
says  the  germs  of  the  disease 
known  as  "  pink-eye  "  are  car- 
ried by  very  minute  flies  of  the  genus  Hippelates 
are  known  to  spread  other  diseases  (Fig.  96). 

However,  some  insects  are  valuable  to  man.  The  honejM^ee 
makes  honey;  other  insects  furnish  galls  for  ink;  others,  dye- 
stuffs,  such  as  cochineal;  while  others  serve  as  scavengers, 
and  the  silkworm  (Fig.  97)  furnishes  our  finest  clothes.  The 
bumble-bee  fertilizes  the  clover  blossoms,  other  insects  cross- 
fertilize  the  flowers  of  many  plants,  and  many  serve  as  food  for 
birds.  Thus,  while  some  insects  are  very  harmful  to  us,  others 
are  very  valuable  to  us.  If  we  (with  the  help  of  the  birds) 
exterminate  those  which  are  injurious  and  protect  those  which 


Fig.  96. — Tsetse  fly,  which  causes 
a  disease  of  cattle  in  Africa,  en- 
larged.    (L.  O.  Howard.) 

Other  insects 


126 


BRANCH    ARTHROPODA 


are  beneficial,  our  crops  will  be  the  larger  and  more  profitable, 
and  our  bodies  more  secure  from  disease. 

Classification, — Entomologists  vary  in  their  opinions  as  to 
the  number  of  orders  into  which  the  Class  Insecta  should  be 
divided.  Packard's  "Guide"  (1883)  gives  eight  orders,  while 
Comstock's  "Manual"  (1895)  and  Kellogg's  "American  Insects" 
(1905)  each  give  nineteen  orders.  Kellogg  says,  "  In  the  first 
place  the  author  believes  that  this  classification^  best  represents 
our  present  knowledge  of  insect  taxonomy;  in  the  second  place, 


if 

Fig.  97.— Adult  silkworm:  1,  Head;  2,  3,  4,  5,  6,  7,  8,  9,  10,  12,  rings; 
11,  horn;  13,  three  pairs  of  articulated  legs;  14,  four  pairs  of  abdominal 
or  false  legs;  15,  a  pair  of  false  legs  on  the  last  ring.  (Farmers'  Bull. 
165,  U.  S.  Dcpt.  of  Agriculture.)  I'he  silk  glands  of  caterpillars  are  ho- 
mologous with  the  true  salivary  glands  of  other  insects. — Folsom. 

this  is  the  classification  taught  by  nearly  all  the  teachers  of 
entomology  in  America." 

Students  wishing  to  study  insects  in  detail  should  consult 
either  Comstock's  or  Kellogg's  large  work  on  insects. 


ORDER  I.  AP'TERA  OR  THYSANU'RA 
These  are  small  or  minute  wingless  insects  which  undergo 
no  metamorphosis.  The  body  is  covered  with  hairs  or  scales. 
There  are  several  pairs  of  rudimentary  abdominal  appendages, 
probaV^ly  vestiges  of  abdominal  legs  in  ancestors.  The  mouth 
parts  are  adapted  for  biting.  "  Their  internal  systems  of  organs 
have  a  segmental  character  corresponding  to  the  external  seg- 
mentation of  the  body."2     They  live  in  sugar  boxes  and  pan- 


Comstock's  classification. 


Kellogg,  p.  59. 


EPHEMERIDA 


127 


tries  or  under  leaves,  and  in  the  spring  they  are  sometimes 
found  in  large  numbers  on  the  surface  of  pools  of  water  or  upon 
the  snow. 


Campo'dea  staphyli'nus,  which  is  regarded  as  the  most  primitive  living 
insect,  belongs  to  this  order.     It  is  about  j  inch  long,  white,  wingless, 
and   flat.      Its    body   is   exceedingly 
soft   and   delicate.     It  is  widely  dis-     '^^' 
tributed. 

The  "fish-moth"  (Le  pis' ma  sac- 
chari'na)  of  the  house  (Fig.  98),  which 
is  neither  a  moth  nor  a  fish,  is  sil- 
very white,  with  a  yellowish  tinge 
on  antenna^  and  legs.  It  is  about  \ 
inch  long,  has  three  long  caudal  ap- 
pendages, and  feeds  cliiefly  upon 
sweet  starchy  materials,  often  at- 
tacking starched  clothing  and  the 
pa.ste  of  wall-paper  and  book-bind- 
ings. It  may  be  gotten  rid  of  by 
sprinkling  fresh  pyrethrum  powder 
in  the  places  infest (m1  or  by  sjmiying 
slightly  Willi  iiicotiii  or  formalin. 

The  "spring-tails"  {Colleui'bola) 
have  a  forked  spring  attached  to  the 
next  to  the  last  segment  of  the  ab-  - — 

domen,  by  means  of  which  they  leap 
from  a  few  inches  to  a  foot  in  the  air. 
The  "  snow-fleas  "  collect  in  large 
numbers  on  the  snow  in  spring. 
They  are  often  a  cause  of  great  an- 
noyance where  maple  sugar  is  made. 


Fig.  98. — Lepis'ma  sacchari'na, 
enlarged.  (L.  O.  Howard,  U.  S. 
Dept.  of  Agriculture.) 


Surely  the  insects  of  this 
order,  by  their  simplicity  of 
structure  and  their  similarity 
of  somites,  show  their  worm  ancestry,  though  some  species 
show  much  more  complexity  of  structure.  It  will  be  interest- 
ing for  the  student  to  consider  how,  from  such  a  generalized 
primitive  form  as  Campodea  staphyUnus,  nature  can  produce, 
by  modification  of  parts,  an  insect  of  highly  complex  structure. 


ORDER    II.      EPHEMER'IDA 

The  May-flies,  in  the  atlult  form,  are  insects  of  a  day,  but 
they  pass  two  or  three  years  in  the  larval  stage.  When  they 
emerge  from  their    larval    condition  into  their  winged  form 


128  BRANCH    ARTHROPODA 

they  come  forth  in  myriads  along  streams.  The  authors  saw 
their  dead  bodies  piled  a  foot  deep  on  an  Illinois  river  bridge 
just  under  the  electric  lights.  So  thick  were  they  that  workmen 
came  next  day  and  shovelled  myriads  of  them  into  the  river. 
They  are  fragile,  soft  skinned,  and  long  bodied,  with  four  gauzy 
wings,  of  which  the  anterior  pair  is  much  the  larger.  The 
abdomen  ends  in  long  thread-like  anal  projections.  The 
mouth  parts  are  rudimentary.  Indeed,  the  adults  are  said  to 
take  no  food,  but  to  reproduce  and  die.  The  eggs  are  laid  in 
the  water.  Soon  appear  tiny,  soft-bodied,  wingless  nymphs, 
bearing  leaf-like  fringed  gills  arranged  segmentally  along  the 
sides,  and  two  or  three  many  jointed  anal  appendages.  They 
have  strong  legs  and  can  l)oth  swim  and  walk.  They  lie  on  the 
bottom  of  streams,  and,  with  their  powerful  mandibles  which  are 
adapted  for  biting  and  chewing,  catch  and  devour  other  insects. 
They  eat  plants  also,  and  are  themselves  prized  as  food  by  many 
kinds  of  fishes  and  other  aquatic  animals. 

After  the  ninth  molt  (some  species  have  twenty-one)  the  wing- 
pads  begin  to  develop.  The  nymph  continues  to  grow  and  to 
molt,  until  finally  it  leaves  behind  its  "  water-nymph  skin  " 
and  comes  forth  a  winged  May-fly.  Again  it  sheds  its  skin, 
it  may  be  within  a  few  minutes  or  within  twenty-four  hours,  a 
thin  layer  coming  off  even  from  the  wings.  This  is  the  only 
known  instance  of  an  insect  molting  after  acquiring  its  wings. 

ORDER   III.      PLECOP'TERA 

The  stone-flies  are  comprised  of  a  single  family,  the  Per'lidce. 
These  grayish  or  brownish  insects  (Fig.  99)  are  |  to  1|  incht^s 
long  and  have  four  large  membranous  wings,  but  the  posterior 
pair  folds  up  like  a  fan  when  not  in  use.  Unlike  the  dragon- 
flies,  in  which  the  anterior  and  posterior  wings  are  about  equal 
in  size,  the  posterior  wings  are  much  wider  than  the  anterior 
ones.  The  mouth  parts  are  adapted  for  l)iting,  but  poorly  so 
as  compared  with  those  of  the  dragon-fly.  The  adults  probably 
eat  little.  The  long  antennae  are  many  jointed  and  the  abdomen 
is  often  furnished  with  a  pair  of  many  jointed  bristles  or  fila- 
ments. The  5000  or  6000  eggs  are  probably  well  scattered  in 
the  swift  current  before  dropping  to  the  bottom.     The  meta- 


ODONATA 


129 


morphosis  is  incomplete.  The  nymphs,  hke  those  of  the 
dragon-fly,  are  aquatic.  They  are  provided  with  gills.  Those 
who  advocate  the  aquatic  ancestry  of  insects  believe  that  the 
spiracles  are  the  openings  left  when  the  gills  were  lost,  but  certain 
species  of  stone-flies  retain  their  gills — though  shrivelled  and 
probably  functionless — and  have  wholly  independent  spiracles.^ 


Fig.  99. 


.4  B 

-A,  Stone-fly.     B,  A  nymph  of  a  stone-fly.     (Comstock.) 


The  larvae  of  stone-flies  are  flat  and  cling  closely  to  the  surface 
of  stones  in  the  swiftest  portion  of  the  stream.  They  cannot 
live  in  stagnant  or  foul  water.  Their  resemblance  to  a  fossil 
is  almost  perfect.  This  resemblance  is  their  protection  from 
their  enemies,  the  fishes.  These  larval  stone-flies  are  good  bait 
for  trout. 

ORDER   IV.      ODON'ATA 

Dragon-flies. — To  this  order  again  belongs^  a  single  family,^ 
the  LihcUu'lidce,  or  dragon-flies  (Fig.  100).  They  have  many 
common  names,  as  "  mule-killers,"  "  snake-doctors,"  and 
"  devil's  darning-needles,"  but,  in  spite  of  these  terrifying  names^ 
they  are  all  perfectly  harmless  to  man, 

1  Kellogg,  p.  72. 

^  Kellogg  includes  the  damsel  flies. 

3  Comstock,  p.  90. 


I'M) 


BRANCH    ARTHROPODA 


The  four  finely  netted  membranous  wings  of  the  adult  dragon- 
fly are  long,  narrow,  strong,  and  nearly  equal.  If  unequal,  the 
posterior  wings  are  the  larger.  Each  wing  has  a  joint-like  struc- 
ture near  the  midtUe  of  the  front  margin.     Their  mouth  parts 


Fig.    100 —Dragon-flics 


111    till     liival,    pupal,    and    imago    state. 
(VfUr  Tcnnt-y  ) 


are  adapted  for  biting.  Their  compound  eyes  are  very  large 
and  th(>  antennae  short.  The  metamorphosis  is  incomplete. 
The  eggs  are  laid  in  water  or  attached  to  aquatic  plants. 
They  soon  hatch,  and  the  larva  (Fig.  100),  called  nymphs, 
live  a  predatory  existence.     They  lie  in  wait  for  their  prey. 


ISOPTERA  131 

"  The  fierce  face  of  the  young  dragon  is  all  concealed  "  by  its 
extensible  lower  lip,  which  folds  up.  With  their  strong  jaws  and 
legs  dragon-flies  secure  and  devour  their  prey.  They  devour  vast 
numbers  of  larval  mosquitos  and  are  thus  of  great  use  to  man. 
Finally,  the  full-grown  nymph  creeps  up  some  stem,  and  the 
winged  form  of  the  imago  or  adult  dragon-fly  breaks  through  the 
old  skin  and  flies  away  into  the  air  and  sunshine  to  enjoy  its 
aerial  life  until  the  falling  temperature  ends  its  existence. 
These  beautiful  creatures  may  be  called  creatures  of  the  air,  for 
they  actually  feed  upon  the  wing  and  may  sometimes  be  seen 
poised  in  mid-air  as  if  resting.  The  adult  devours  many  gnats 
and  mosquitos.  There  are  two  types  of  dragon-flies,  one 
which  keeps  its  wings  horizontal  and  one  which  folds  its  wings 
together  vertically  over  the  back.^ 

The  breathing  of  the  nymphs  is  peculiar.  "The  caudal  end 
of  the  alimentary  canal  is  lined  with  tracheae,  and  water  is 
alternately  drawn  into  and  expelled  from  this  cavity.  The 
water  may  be  expelled  with  such  force  as  to  propel  the  body 
forward.     So  this  has  a  locomotive  function  also." 

ORDER   V.      ISOP'TERA 

The  Termites  (Fig.  101),  or  so-called  "white  ants,"  are  abun- 
dant in  the  tropics,  but  less  so  in  the  United  States.  Where 
they  are  numerous  they  become  pests,  destroying  houses,  furni- 
ture, or  anything  made  of  wood.  They  are  not  ants,  as  may  be 
seen  by  their  structure. 

The  body  is  always  soft  and  usually  whitish  in  color,  though 
sometimes  brown.  "  It  is  plump  and  slightly  broader  than 
thick."  In  the  vmion  of  the  abdomen  with  the  thorax  the  little 
pedicel  or  stem  found  in  the  ant  is  lacking,  the  abdomen  being 
broad  at  the  base.  They  are  blind  or  have  simple  eyes.  They 
conceal  themselves  from  the  light.  The  slender  antennae  look 
like  strings  of  tiny  beads. 

The  young  are  all  apparently  alike  when  hatchinl,  but  by 

some  means  not  understood  they  are  afterward  developed  into 

soldiers,  workers,  males   (kings),  and  females   (queens).     The 

winged  males  and  females  swarm,  and  each  pair  which  is  fortu- 

1  Damsel  flies,  Kellogg. 


132 


BRANCH    ARTHROPODA 


nate  enough  to  escape  being  eaten  by  birds  finds  a  place  for  a  nest, 
or  is  taken  possession  of  by  workers,  and  a  new  colony  is  founded. 
The  males  and  females  lose  or  divest  themselves  of  their  wings. 
Termites  usually  feed  upon  rotten  wood,  but  some  species 
attack  soft  plants  and  live  wood,  or  even  cloth,  pajier,  and  leather. 
In  Africa  these  insects  sometimes  build  pyramidal  nests  twenty 
feet  high  and  form  villages  of  them.    They  are  so  numerous 


Fig. 


101. — White  ant   {Termes  flavipes): 
worker;  d,  soldier;  e,  queen; 


I,  Larva;  b,  winged  male;  c, 
pupa.     (Riley.) 


and  Ijold  that  "  nothing  can  defy  the  marauders  but  tin  or 
iron."^  Many  species  of  insects  have  been  found  living  a  com- 
mensal life  with  termites,  *'  a  sort  of  insect  economy  termed 
termitophily." 

ORDER   VI.      ORTHOP'TERA 

This  order  comprises  some  of  our  most  familiar  insects,  as 
the  cockroaches,  mantids,  leaf-insects,  walking  sticks,  short- 
horned  grasshoppers  (locusts),  long-horned  grasshoppers,  and 
crickets. 

The  Orthoptera  usually  have  two  pairs  of  wings.  The 
anterior  wings  are  thicker  and  overlap  or  cover  the  posterior 
wings  when  the  insect  is  at  rest.  The  walking-stick  is  wingless. 
1  Drummond. 


ORTHOPTERA  133 

The  grasshopper  (see  Fig.  85,  p.  113)  may  be  taken  as  typical  of 
this  order. 

The  Head. — The  mouth  parts  consist  of  a  lahrum  or  upper 
lip,  the  mandibles,  a  pair  of  crushing  or  biting  jaws,  followed 
by  a  pair  of  maxillce.,  or  smaller  jaws,  each  of  which  consists  of 
three  parts — ^an  outer,  jointed  maxillary  palpus,  and  a  spoon- 
shaped  piece  which  covers  the  brown  incurved  maxilla.  Then 
follows  the  labium,  or  lower  lip,  with  its  jointed  labial  palpi. 
On  the  head  are  two  compound  eyes  and  three  simple  eyes, 
or  ocelli,  and  a  pair  of  antennae  or  feelers. 

The  thorax  is  divided  into  three  well-marked  divisions: 
First,  is  the  movable,  cape-like  prothorax,  to  which  is  attached 
the  first  pair  of  legs.  Second,  is  the  mesothorax,  bearing  the  next 
pair  of  legs  and  the  anterior  pair  of  wings,  which  are  straight 
and  rather  narrow.  Third,  is  the  metathorax,  with  the  large 
third  pair  of  legs  and  the  posterior  wings,  which  fold  up  like  a 
fan  under  the  anterior  wings  when  not  in  use. 

The  segmented  abdomen  follows  the_  thorax.  Close  observa- 
tion with  the  magnifying  glass  will  show  minute  openings  on  the 
sides  of  the  segments.  These  openings  are  the  spiracles  or 
breathing  pores. 

"  Singing." — This  order  of  insects  gives  us  most  of  our 
"  singers  "  and  leapers  of  the  insect  world,  and,  strangely  enough, 
the  leapers  are  the  singers,  and,  stranger  still,  they  sing  without 
a  voice.  Of  the  six  families  of  Orthoptera,  three  are  composed 
of  these  leaping  and  "  singing  "  insects.  The  locust  or  short- 
horned  grasshopper,  when  at  rest,  makes  a  noise  by  rasping  the 
inner  surface  of  the  hind  thighs  across  the  thickened  and  ridged 
longitudinal  vein  of  the  outer  surface  of  the  fore  wings.  In  the 
air,  the  "  clacking  "  is  made  by  rubbing  the  upper  surface  of  the 
anterior  margin  of  the  hind  wings  back  and  forth  past  the 
under  surface  of  the  posterior  margin  of  the  fore  wings.  "  This 
can  be  heard  for  a  distance  of  several  rods."^ 

The  male  cricket  holds  his  fore  wings  (Fig.  102)  up  over  his 
body  and  rubs  together  the  upper  side  of  their  basal  region. 
The  male  tree  crickets,  katy-dids,  meadow-green  grasshoppers 
with  long  antennae,  also  rub  together  specially  modified  por- 
tions of  the  fore  wings. 

1  Kellogg,  p.  134. 


134 


BRAXf'H  ARTHROPODA 


Hearing. — The  "  ears  "  c(jnsist  of  a  i^air  of  small  tympanic 
membranes,  situated  on  the  basal  segment  of  the  abdomen  in 
the  locust  and  on  the  tibiae  of  the  forelegs  (Fig.  95,  p.  123) 
of  the  cricket  and  katy-did.  Associated 
with  each  tympanum  is  a  vesicle  filled 
with  liquid  and  an  auditory  ganglion,  which 
is  conn(^cted  by  a  nerve  with  one  of  the 
thoracic  ganglia. 

Feeding. — All  Ortho])t(>ra  have  biting 
mouth  parts,  and  bite  off  and  chew  their 
food.  Most  of  them  are  vegetable  feeders, 
but  the  mantis  is  carnivorous.  The  locusts 
or  grasshoppers  have  at  times  wrought 
great  havoc  with  man's  crops,  as  both 
sacred  and  secular  history  tell  us. 

Leaping. — In  the  leaping  Orthoptera  the 
posterior  pair  of  legs  is  especially  adapted 
for  this  purpose.  They  are  large  and  long, 
and  when  walking  the  knee-joints  are  much 
higher  than  the  insect,  thus  giving  leverage  for  their  prodigious 
leaps,  in  which  they  rival  the  fleas  in  their  athletic  records. 

The  metamorphosis  is  incomplete,  the  young  (nymphs) 
(Fig.  103)  differing  from  the  parents  in  size  and  absence  of  wings 
(Fig.  104). 


Fig.  102.— Wing 
of  cricket  musician 
(enlarged) ,  showing 
the  file  at  a  and  the 
scraper  at  b. 


Fig.  103. 


-Calopt'etms  spre'luti:  a,  a,  Newly  hatched  larva" 
larva;  r,  pupa,  natural  size.     (After  Riley.) 


h,  full-grown 


The  cockroaches  { Blat' tidm)  are  nocturnal  insects,  found  about  the 
pantries  and  water-pipes  of  our  dwellings,  though  in  the  North,  according 
to  Comstock,  our  native  species  lives  in  woods  and  fields.  One  may  often 
find  them  hiding  under  bark,  sticks,  and  stones.  The  jaws  are  strong  and 
toothed,  and  they  are  greedy  little  creatures,  devouring  anything  they  can 
get,  "  eating  book-bindings  and  bed-bugs  with  equal  alacrity."  The  body 
is  flat  and  slippery  and  the  legs  are  adapted  for  rapid  running,  enabling 


ORTHOPTERA 


135 


them  to  escape  readily  into  cracks  and  crevices.     Cockroaches  were  the 
dominant  insects  in  carboniferous  times.     There  are  four  common  species, 


Fig.  104. — Calopi'enus  spre'tus.  Process  of  acqviiring  wings:  n,  Pupa 
with  skin  just  spht  on  the  back;  b,  the  imago  extending;  c,  the  imago  nearly 
out;  d,  the  imago  with  wings  expanded;  e,  the  imago  with  all  parts  perfect, 
natural  size.     (After  Riley.) 


Fig.  105. — African  mantis  or  soothsayer,  with  its  egg-mass.     (Monteiro.) 

only  one  being  native  to  the  United  States.     The  eggs  are  laid  in  small, 
bean-shaped,    horny,    brown    cases.     The    young    are    preeocial.     Cock- 


130 


BRANCH    ARTHKOPODA 


roaches  may  be  gotten  rid  of  by  dusting  fresh  insect-powder  into  the 
cracks  of  pantry  and  kitchen  with  a  httle  hand-bellows. 

The  praying  mantids  {Man'tida:)  (Fig.  105)  are  peculiar  insects  which  get 
their  name  from  the  attitude  in  which  they  watch  for  their  prey.  They 
stand  motionless  with  the  head  raised  upon  the  long  prothorax  and  the 
front  legs  clasped  in  front  of  the  face.  These  front  legs  are  spiny  and  are 
used  only  for  seizing  and  holding  their  prey.  The  wings  are  usually  leaf- 
like in  color  and  texture,  and  this  special  -protective  resemblance  is  very 
good  when  the  insect  rests  upon  a  plant.     They  are  carnivorous  and  do 


Fig.  106. — A  walking-stick  among  the  stems  of  a  flower-cluster.     (From 
life.) 


much  good  in  destroying  insect  pests,  so  much  indeed  that  Professor  Slinger- 
land  is  trying  to  establish  and  distribute  a  European  species  in  the  United 
States.  Most  of  the  mantids — less  than  a  score  of  species — are  tropical. 
Our  most  common  native  species,  Phasmom''tn'tis  caroli'na,  is  about  2§ 
inches  long.  They  are  everywhere  regarded  with  strange  superstition, 
and  the  superstitious  say  one  should  "  never  kill  a  mantis,  as  it  bears 
charm  against  evil."  A  Japanese  mantis  {Tinode'ra  sinen'sis),  recently 
introduced  into  the  United  States,  is  brown.  This  protection  conceals 
the  insect  not  only  from  its  enemies,  but  from  its  prey,  for  which  it  "  heg 


ORTHOPTERA 


137 


in  wait,"  and  may  thus  be  called  aggressive  resemblance.  Several  species 
from  India  resemble  flowers,  and  thus  attract  insects,  upon  which  they 
feed.     This  is  an  exanii)le  of  (illurnu/  colors. 

The  walking-sticks  [Phas'inidn)  (Fig.  106)  afford  even  better  examples 
of  special  protective  resemblance   than   the  mantids.      Our   species    are 
wingless  and  may  be  either  green  or  brown,  and  are  usually  found  upon 
twigs  of  a  color  corresponding  to  that  of  their  bodies.     The  body,  which 
is  long,  straight,  and  slender,  looks  exactly  like  a  twig,  while  the  slender 
legs  look  like  so  many  tiny  branches.     One  may  pick  up  a  walking-stick, 
thinking  it  a  twig  until  it  moves.    Although  it  is  so  repulsive  to  the  unin- 
itiated, it  is  a  perfectly  harmless  creature.    The  only  common  species  in  the 
northern  states,  Didplicron/'i m  j'< mara'ta,  "  feeds  upon  the  leaves  of  oaks 
and  other  trees.     It   drops  its  liundrcd  seed- 
like  eggs   loosely  and  singly   on  the  ground,  l 
where  they  lie  through  the  winter,  hatching  \ 
irregularly  through    the  following  summer,''^  1 
or  even  the  second  summer.     Over  six  hun- 
dred species  of  this  family  are  known.     They 
are  numerous  in  the  tropical  and  sub-tropical 
countries  and   present  many  striking  resem- 
blances to  their  environment,  one  of  the  most 
perfect  of  which  is  the  "green-leaf  insect" 
(Fig.  90,  p.  117).      Its  wings,  flat  body,  ex- 
panded legs,  and   even  head   and   prothorax 
are  bright  green  flecked  with  yellow,  making 
it  look  wonderfully  like  a  leaf  attacked  by 
fungi. 

"  The  locusts  or  short-horned  grasshoppers 
(Acrid' idir)  include  those  '  grassh()])])('rs  '  in 
which  the  antenna^  are  shorter  than  the  body, 
and  in  which  the  ovipositor  of  the  female  is 
short  and  made  up  of  four  separate  plates. "- 
The  tarsi  have  three  joints.  The  first  ab- 
dominal segment  has  a  tympanic  membrane 
on  each  side.  It  is  to  this  family  that  the 
locusts  mentioned  in  the  Bible  and  in  his- 
tory belong,  as  well  as  those  which  have 
wrought  such  havoc  in  our  own  country. 
A  conspicuous  species  is  the  common  red- 
legged  locust,  Melan'oplus  fe'mur-ru'brum. 
There  are  about  five  hundred  species  of  this 
family  in  the  United  States,  but  only  three  or 
four  of  them  are  migratory.  These  go  in  swarms,  sometimes  so  dense 
as  to  obscure  the  sun  as  a  great  cloud,  and  when  they  alight  they  literally 
devour  every  green  thing  in  that  region.  The  largest,  most  injurious,  and 
most  numerous  of  these  are  the  Rocky  Mountain  locusts  (Melan'oplus 
spre'tus).  Their  permanent  breeding-grounds  are  upon  the  western  pla- 
teaus, from  2000  to  10,000  feet  above  sea  level,  and  they  cannot  endure 
for  successive  generations  the  low,  moist  land  of  the  Mississipj)!  X'alley. 
"  These  locusts  show  a  tendency  to  become  gregarious  from  the  begiiuiing 
of  their  life  as  nymphs.     A  recent  method  of  fighting  them  is  to  cultivate 

'  Kellogg. 
^  Comstock. 


Fig.  107.— Carolina  lo- 
cust killed  by  a  fungus. 
(Bulletin  No.  81,  New 
Hampshire  Experiment 
Station  Insect  Record, 
1900.) 


138 


BRANCH    ARTHROPODA 


in  a  sweet  solution  a  destructive  fungous  growth  (Fig.  107) .  A  few  members 
of  the  swarm  are  dipped  in  the  solution  and  turned  loose,  spreading  the 
disease.!  Melan'oplus  (ill<ui'lis  sometimes  docs  much  harm  in  New  England. 
Locusts  lay  their  cgg^,  numbering  from  2.5  to  125,  in  oval  masses,  cov- 
ered with  a  glutinous  substance.  The  female  deposits  them  (Fig.  108)  in 
the  ground  or  in  rotten  wood,  with  hor  strong,  horny  ovipositor,  or  they 
may  be  laid  on  the  surface  of  the  ground  among  the  grass  and  weeds.  The 
eggs  are  usimlly  laid  in  the  fall  and  hatch  in  the  spring,  there  being  but  the 
one  new  brood  a  year.  The  young  resemble  the  parents  in  general,  having 
biting  mouth  i)arts  and  long  legs.  They  are  paler  and  wingless.  The 
wings  appear  as  minute  scale-like  projections  and  grow  larger  with  each  of 
the  five  or  six  molts  (Fig.  104)  Strangely  enough,  the  himl  wings,  which 
are  always  underneath  tlie  fore  wings  in  the  adult,  lie  outside  during  devel- 
opment.    Birds  are  the  best  exterminator.     The  eggs  may  be  jjlowed  up 


Fig.  108.— Rocky  Mountain  locust :  a,  u,  a,  Female  in  different  positions, 
ovipositing;  h,  egg-pod  extracted  from  ground,  with  the  end  broken  open; 
c,  a  few  eggs  lying  loose  on  the  ground;  d,  e,  show  the  earth  partially  removed 
to  illustrate  an  egg-mass  already  in  place  and  one  being  placed;  /,  shows 
where  such  a  mass  has  been  covered  up.     (After  Riley.) 


in  the  fall,  or  when  they  hatch  in  the  spring  the  young  could  be  crushed  by 
heavy  rollers  or  burned  by  scattering  straw  over  the  ground  and  lighting  it.^ 
Locus'tidae. — This  family  includes  crickets,  katy-dids,  and  long-horned 
grasshoppers.  Unfortunately,  the  common  name  of  locust  is  applied  only 
to  members  of  the  family  of  Acrididoe,  and  to  the  cicada  of  the  order 
Hemiptera,  hut  to  none  of  the  LocM.s/w/ce.  The  long-horned  meadow-green 
grasshopper  has  the  delicate  antennae  longer  than  the  body,  the  tarsi 
four  jointed,  the  ovipositor  sword  shaped,  and  the  tympanum  on  the 
tibia  (Fig.  95,  p.   123)  of  the  front  leg.     The  males  call  their  mates  by 

1  Linville-Kelly,  p.  15. 

2  Kellogg,  p.  139. 


ORTHOPTERA  139 

rubbing  together  the  specially  modified  wing  covers.  These  grasshoppers 
abound  in  our  meadows  everywhere.  If  you  would  know  how  perfect  is 
their  protective  resemblance,  try  to  find  one  which  you  have  seen  on  the 
wing,  after  it  has  alighted.  Some  species  found  in  caves  are  wingless, 
colorless,  and  blind.  Their  antenna?  and  hind  legs  are  developed  to  a  great 
length. 

The  katy-dids,  of  which  there  are  several  genera,  are  rather  large,  usually 
green  insects.  They  live  upon  trees  and  shrubs,  feeding  upon  foliage  and 
tender  branches,  though  they  sometimes  eat  animal  food.  Only  the  males 
tell  us  "  Katy  did  "  or  "  she  didn't."  They  usually  "  sing  "  at  night  from 
July  or  August  until  frost.  They  are  not  gregarious.  Their  thin,  finely 
veined  wings  are  almost  indistinguishable  in  the  foliage. 

Closely  allied  to  the  katy-dids,  but  looking  more  like  crickets,  are  the 
wingless   grasshoppers,    the  cricket-like  grasshoppers,  and  shield-backed 


Fig.  109. — Mole  cricket  {Gryllotal'paboria'lis).     (Burmeister.) 

grasshoppers.  They  are  dull  colored  and  live  under  stones  and  rubbish 
or  loose  soil. 

The  crickets,  of  which  there  are  few  species,  have  the  wing  covers  flat 
and  overlapping'above,  and  bent  sharply  down  at  the  edge  of  the  body  like 
a  box  cover.  The  antenna?  are  long  and  the  ovipositor  is  spear  shaped. 
Thej^  include  the  mole  crickets,  true  crickets,  and  tree  crickets. 

Mole  crickets  (Fig.  109)  are  fitted  for  a  burrowing  life.  The  front  tibiae 
are  broadened  and  shaped  somewhat  like  the  feet  of  a  mole.  They  feed 
upon  the  tender  roots  of  plants,  and  .sometimes  injure  potatoes  (Fig.  110). 

The  (rue  crickets,  our  familiar  black  species,  live  in  houses  or  fields. 
They  usually  feed  upon  plants,  but  some  are  predaceous.  The  eggs,  laid 
in  the  fall,  usually  in  the  ground,  hatch  in  summer.  Only  a  few  of  the 
old  crickets  survive  the  winter. 


140  BRANCH    ARTHROPODA 

The  tree  crickets  live  in  trees  or  on  tall  plants.     The  female  "  snowy 
tree  cricket  "  does  much  damage  by  laying  her  eggs  in  grapevines  or  rasp- 


Fig.  110. — Potato  injured  by  mole  cricket. 

berry  canes,  causing  them  to  die  above  the  puncture.     These  canes  should 
be  cut  and  burned  in  winter  or  early  spring  before  the  eggs  hatch. 

ORDER   VII.      HEMIPTERA 

This  order  contains  some  of  our  most  common  and  destruc- 
tive insects,  as  the  chinch-bug,  the  grape  phyllox'era,  the  San 
Jose  scale,  the  bed-bug  (Fig.  HI),  the  louse,  the  squash  bug, 
stink-bugs  of  various  kinds,  plant-lice  (Aphid'idcB) ,  and  bark-lice 
(Coc'cidce),  which  furnish  dye-stuffs,  as  cochineal,  stick-lac,  from 
which  we  get  shellac,  and  China  wax. 

The  Hemip'tera  include  some  five  thousand  species  in  North 
America.  All  of  these  species  agree  in  that  the  mouth  parts 
are  modified  into  a  piercing  and  sucking  beak.  Their  food,  con- 
sequently, is  the  blood  of  men  or  of  other  animals  or  the  juices 
of  plants.    The  sucking  beak  consists  of  the  labium,  which,  to- 


HEMIPTERA 


141 


gether  with  the  labial  palpi,  is  modified  into  a  jointed  sheath. 
This  incloses  the  mandibles  and  maxillae,  which  are  changed 
into  long,  piercing  stylets.^  The  labrum  or  upper  lip  is  small  or 
rudimentary.  There  are  usually  four  wings.  In  the  typical 
Hemiptera,  as  exemplified  in  the  sub-order  Heterop'tera,  the 
character  of  the  anterior  wings  is  a  distinguishing  feature. 
The  basal  portions  of  these  wings  are  thickened  and  parch- 
ment-like, while  the  terminal  portions  are  membranous  and 
overlap  when  the  wings  are  folded  over  the  back.  From  the 
character  of  these  wings  the  order  gets  its  name — hemi,  half, 


'Fig.  111. — Bed-bug  (Ci'mex  lectular'ius):  a,  Adult  female  gorged  with 
blood;  b,  same  from  below;  c,  rudimentary  wing-pad;  d,  mouth  parts. 
All  enlarged.  (Marlatt,  Bull.  U.  S.  Dept.  of  Agriculture,  1896.)  "The 
characteristic  odor  of  bugs  is  due  to  the  secretions  of  certain  stink  glands, 
which  in  the  young  open  on  to  the  upper  surface  of  the  abdomen  and  in  the 
adult  open  on  each  side  of  the  metasternum." — Sedgwick. 


and  pteron,  a  wing,  i.  e.,  the  Hemip'tera  or  "  half-winged  " 
insect.  The  second  pair  of  wings  are  membranous  and  fold  un- 
der the  fore  wings  when  not  in  use.  The  electric-light  bugs, 
bed-bugs,  water-bugs,  and  squash-bugs  are  familiar  examples. 
In  the  sub-order  Homop'tera  the  anterior  wings  are  not  thick- 
ened, but  are  of  the  same  structure  throughout,  as  in  the  cicada. 
In  the  sub-order  Parasl'ta  are  found  wingless  parasitic  hemip- 
tera which  prey  upon  certain  mammals,  for  example,  the  head 
and  body  lice  of  man,  dogs,  cattle,  hogs,  sheep,  mice,  and 
rabbits. 

1  See  Kellogg,  p.  164. 


142 


BRANCH    ARTHKOPODA 


The  giant  water-bugs  {Bdostom'idce)  are  an  example  of  the  largest 
Heteroptera  or  true  bugs.  They  are  often  seen  about  electric  lights.  They 
fly  from  pond  to  pond  and  are  very  rapacious,  feeding  upon  the  juices  of 
young  fishes,  insects,  and  tadpoles. 

The  chinch-bug  family  {Lygoe'idce}  has  nearly  two  hundred  species  in  the 
United  States.  The  most  destructive  is  the  small  but  widely  distributed 
chinch-bug  {BHs'sus  leucop'terus)  (Fig.  112),  and  though  it  measures  less 
than  ^  inch  in  length,  it  costs  the  United  States  $20,000,000  annually,  for 
it  is  "  the  worst  pest  of  corn  and  one  of  the  worst  of  wheat."  There  are  two 
generations  of  the  chinch-bug  annually.  The  adults  winter  under  rubbish, 
and  in  early  spring  they  lay  their  eggs  in  fields  of  grain  upon  roots  or  stems 
beneath  the  soil.  They  hatch  in  about  two  weeks,  and  the  little  red  nymphs 
attack  the  root  and  then  the  stalk  of  the  wheat.  They  mature  in  about 
six  or  .seven  weeks,  when  they  are  "  blackish,  with  the  wings  semitransparent 
white,  and  with  a  conspicuous  small  triangular  black  dot  near  the  middle 
of  their  outer  margin."     At  about    harvest    time  they    migrate  by    the 


Fig.  112. — The  chinch-bug  {Bliti'sus  leucop'terus):  a,  b,  Eggs;  c,  newly 
hatched  larva;  d,  its  tarsus;  e,  larva  after  first  molt;  /,  same  after  second 
molt;  g,  pupa — the  natural  sizes  indicated  at  sides;  h,  enlarged  leg  of  per- 
fect bug;  j,  tarsus  of  same  still  more  enlarged;  i,  proboscis  or  beak,  en- 
larged.    (Riley.) 


millions  to  fields  of  growing  corn,  marching  in  a  body  like  an  approaching 
army.  When  the  bugs  of  the  first  brood  have  reached  maturity,  they  pair, 
at  which  time  only  they  use  the  wings,  and  the  second  generation  is  begun. 
The  adults  of  the  second  generation  that  survive  the  winter  lay  the  eggs 
for  the  spring  brood.  It  is  thought  that  a  third  brood  sometimes  appears 
in  Kansas. 

Their  migration  from  wheat  to  corn  fields  may  be  hindered  by  plowing 
furrows  around  the  fields  and  pouring  crude  petroleum  or  coal-tar  into  these 
moats.  If  this  has  not  been  done,  when  the  bugs  collect  on  the  first  few 
rows  of  corn  they  should  be  sprayed  at  once  with  kerosene  emulsion. 
Predaceous  insects,  as  the  aphis-lion  and  ladybird  beetles,  and  birds  hold 
them  in  check.  But  a  parasitic  fungus  (Sporotri'chum  glohulif'erum) 
will  kill  the  bugs  rapidly  in  moist,  warm  weather. 

The  cicadas  {Cicnd'idce)  are  easy  of  recognition  on  account  of  their 
large,  blunt-headed,  robust  bodies,  the  three  ocelli,  and  their  shrill  "  sing- 
ing "  during  the  daytime  in  the  late  summer  and  early  fall.  The  male 
does  all  the  talking  or  singing,  if  you  choose  to  call  it  a  song,  and  "  his  wife 


HEMIPTERA 


143 


cannot  talk  back."  The  sound  is  made  by  "  stretching  and  relaxing  a  pair 
of  corrugated  tympana  or  parchment-like  membranes  by  means  of  a 
muscle  attached  to  the  center  of  each.''^ 

The  strangest  freak  in  all  insect  life  is  the  periodical  cicada  or  seventeen- 
year  locust  (Fig.  113).  It  is  the  longest  lived  of  all  insects,  for  while 
other  insects  jiass  from  the  egg  to  imago  form  in  a  few  days  or  weeks,  or,  at 
the  most,  in  one  to  three  years,  this  insect  requires  from  tiiirteen  to  seven- 
teen years  for  this  development.  In  the  spring  the  female  cuts  slits  in 
tender  twigs  and  lays  her  eggs  therein.  In  about  six  weeks  they  hatch 
and  the  nymphs  spend  the  required  seventeen  years,  or,  in  the  case  of  a 
southern  form,  thirteen  years,  in  the  ground.  They  feed  by  sucking  the 
juices  of  tender  roots.  In  the  spring  of  the  seventeenth  or  the  thirteenth 
year — as  the  case  may  be — they  crawl  up  to  the  surface  of  the  ground, 


Fig.  113. — The  seventeen-year  Cicada  (c)  and  pupa  (a,  b);  d,  position  of 
eggs  (e);  /,  larva.     (Riley.) 


undergo  their  last  molting,  and  emerge  as  clear-winged  cicadas.  This 
insect  is  a  fine  example  of  protective  resemblance.  One  may  be  within 
a  few  inches  of  a  "  singing  "  cicada  and  not  be  able  to  see  it,  so  near  the 
color  of  the  tree  trunk  or  ground  is  it.  The  adult  life  is  short.  They  lay 
their  eggs,  sing  th- ir  songs,  and  die. 

The  plant-lice  or  aphids  [Aphid'ida')  are  among  our  most  common  and 
destructive  pests  in  the  green-house,  field,  ai'(l  orchard.  There  are  many 
species,  most  of  which  are  small,  the  larg(^st  barely  reaching  the  length  of 
J  inch.  The  small,  soft,  usually  green  body  is  somewhat  pear  shaped. 
Wingless  forms  are  most  numerous,  but  there  are  forms  in  almost  every 
brood  which  have  two  pairs  of  delicate  transparent  wings,  the  anterior 
pair  of  which  is  the  larger.     "  The  two  wings  of  each  side  are  usually  con- 

1  Kellogg,  p.  167. 


144  BRANCH    ARTHROPODA 

nected  with  a  compound  booklet."^  The  sucking  beak  is  three  jointed 
and  may  or  may  not  be  longer  than  the  body.  They  have  prominent  com- 
pound eyes  and  usually  oc^elli.  The  long  antennae  are  from  three  to  seven 
jointed.  Many  species  have  on  the  sixth  segment  of  the  abdomen  two 
tubular  processes,  long  supposed  to  be  the  honey  tubes,  but  Kellogg  says 
"  from  them  issues  another  secretion,  not  sweetish,  about  which  little  is 
known,"  and  that  the  "honey-dew"  so  relished  by  ants  (p.  179)  "is 
now  known  to  be  an  excretion  from  the  intestine  issuing  in  fine  droplets 
or  even  spray  from  the  anal  opening."  It  is  sometimes  produced  in  large 
quantities,  so  that  the  leaves  below  the  plant  lice  are  coated  with  it  and  the 
walks  beneath  the  trees  spotted  by  it.  It  is  fed  upon  by  bees  and  wasps 
as  well  as  by  ants.  In  addition  to  the  "honey-dew,"  many  species  secrete 
another  fluid,  which  is  excreted  as  a  liquid  through  "  various  small  open- 
ings scattered  over  the  body."  This  Uquid  soon  hardens  into  a  wax. 
The  total  waxy  secretion  appears  as  a  mass  of  felted  threads  or  wool,  as  in 
the  wooly  apple  aphis,  and  probably  serves  as  a  protection  for  the  soft, 
defenseless  body. 

The  aphids  are  remarkably  variable  as  regards  their  reproduction  sexually 
or  agamically,-  and  as  regards  their  possession  of  wings,  so  that  the  life- 
history  varies  not  only  in  different  species,  but  in  the  same  species  under 
different  conditions.  The  eggs  are  laid  in  the  fall,  and  from  them  hatches, 
in  early  spring,  a  colony  of  wingless  individuals  which  may  produce  (without 
pairing)  either  living  young  or  eggs.  This  may  continue  under  favorable 
food  supply  and  temperature  for  a  number  of  generations.  Slingerland, 
of  Cornell  University,  reared  four  generations  of  wingless  "  agamic  " 
aphids.  At  any  time,  especially  if  food  becomes  scarce  or  other  conditions 
unfavorable,  winged  individuals  are  likely  to  appear  and  fly  away  to  other 
host  plants,  where  they  produce,  agamically,  new  colonies.  If  temperature 
becomes  low  or  other  unfavorable  conditions  occur,  these  asexual  individuals 
produce  a  brood  consisting  of  both  males  and  females.  "  The  males  may 
be  either  winged  or  wingless,  but  the  females  are  always  wingless."  These 
sexual  forms  pair  and  produce  one  or  more  large  fertilized  eggs  which  lies 
dormant  over  winter  and  hatches  into  a  wingless  "  stem-mother  "  in  the 
spring,  and  a  series  of  agamic  generations  follow.  The  multiplication  of 
aphids  is  so  rapid  that,  were  it  not  for  predaceous  insects,  such  as  lady- 
bird beetles,  aphis-lions,  and  parasitic  Hymenop'tera,  and  for  insect-loving 
birds  (see  Birds),. they  would  utterly  destroy  their  host  plant  and  ulti- 
mately starve  themselves.  Professor  Forbes  made  an  estimate  of  the  rate 
of  increase  of  the  "  corn-louse,"  and  found  that  if  "  all  the  plant-lice  de- 
scending from  a  single  '  stem-mother  '  were  to  live  and  reproduce  through- 
out the  year  we  should  have  coming  from  the  egg  the  following  spring 
9,500,000,000,000  young.  As  each  plant-louse  measures  about  1.4  mm. 
in  length  and  0.93  mm.  in  width,  an  easy  calculation  shows  that  these 
possible  descendants  of  a  single  female  would,  if  closely  placed  end  to  end, 
form  a  procession  7,850,000  miles  in  length." 

Aphids  vary  greatly,  in  their  feeding  habits,  many  feeding  upon  the 
juices  of  tender  leaves,"  stems,  leaf-buds,  or  blossom-buds,  while  others 
.suck  the  juices  of  tender  roots  in  the  soil,  and  sometimes  the  same  species 
lives  both  above  and  below  ground.  Above  ground  they  may  be  fought 
by  strong  solutions  of  soap,  by  kerosene  emulsion,  or  by  a  weak  solution  of 
nicotin.  Since  they  suck  the  juices  of  plants  they  cannot  be  affected  by 
poisoning  the  food.      Underground,  carbon  bisulphid  is  sometimes  used, 

1  Comstock.  2  Glossary. 


HEMIPTERA 


145 


but  about  the  best  remedy  is  to  destroy  the  infested  tree  or  vine,  and  plant 
one  of  another  species  which  is  not  a  host-plant  for  the  pest. 


Fig.  114. — Phyllijxe'ra  vastci'irix:  a,  Leaf  with  galls;  b,  section  of  gall 
showing  mother  louse  at  center  with  young  clustered  about;  c,  egg;  d, 
larva;  e,  adult  female;  /,  same  from  side,  (a,  Natural  size;  b-f,  much 
enlarged) .     (Marlatt . ) 


Fig.  115. — Phylloxe'ra  vasta'trix:  a,  Root-galls;  b,  enlargement  of  same,  show- 
ing disposition  of  lice;  c,  root-gall  louse,  much  enlarged.     (Marlatt.) 


The  grape  Phylloxe'ra  (Fig.  114)  is  a  native  aphid  found  upon  the  wild 
grapevines   of   the   eastern  United  States.     It   was  introduced   into   the 
south  of  France  before  1863  upon  rooted  vines  sent  from  America,  and, 
10 


14(3 


BRANCH  ARTHROPODA 


curiously  enough,  says  Kellogg,  "came  to  California — in  which  state  it  has 
done  much  more  damage  than  elsewhere  in  our  country — from  France,  in- 
troduced upon  imported  cuttings  or  roots  "  (Fig.  115).  Probably  not  less 
than  30,000  acres  of  vineyards  have  been  destroyed  by  it  since  it  was  first 
noticed  in  1874.  "  The  Phylloxera  appears  in  four  forms:  (1)  the  gall 
form,  hving  in  little  galls  on  the  leaves  (Fig.  114),  and  capable  of  very 
rapid  multiplication  (this  form  rarely  appears  in  California) ;  (2)  the  root 
form  (Fig.  115),  which  is  derived  from  individuals  which  migrate  from 
the  leaves  to  the  roots,  and  which  by  the  piercing  of  the  roots,  sucking  the 
sap,  and  producing  little  quickly  decaying  tubercles  on  the  rootlets,  does 
the  serious  injury;  (3)  the  winged  form  (Fig.  116),  which  flies  to  new  vines 
and  vineyards  and  starts  new  colonies;  and,  finally,  (4)  the  sexual  forms, 


Fig.   116. — Phylloxe'ra  vasta'lrix:  a,   Migrating  stage,  winged  adult;  b, 
pupa  of  same;  c,  mouth  parts  with  thread-like  sucking  setse  removed  from 


sheath;  d  and 
(Marlatt, 


e,  eggs  showing  characteristic  sculpturing;  all  enlarged 


male  and  female  (Fig.  117),  which  are  the  regenerating  individuals,  ap- 
pearing after  several  agamic  g«'n(>rations  have  been  produced."  The  gall 
stage  may  be  omitted,  and  the  in(li\iduals  hatched  from  the  fertilized  eggs 
go  directly  to  the  roots.  The  gall  form  can  be  prevented  by  spraying  to 
kill  the  winter  eggs.  But  about  the  only  real  cure  for  the  infested  roots  is 
to  dig  them  up  and  burn  them  and  plant  out  resistant  vines.  The  wild 
vines  of  the  Mississippi  Valley  have  evolved  with  the  Phylloxera,  and  are 
capable  of  living  and  growing  in  spite  of  the  pests.  The  French  vine- 
yards, as  well  as  those  of  California,  are  being  renewed  by  grafting  French 
stocks  upon  the  resistant  roots,  thus  rendering  the  vines  practically  im- 
mune. There  are  many  species  of  aphids,  but  this  example  must  suffice  for 
our  present  work. 

Scale-bugs,  mealy-bugs,  and  others  (Coc'cidae)  compose  a  very  anomalous 


HEMIPTERA 


147 


group,  the  species  differing  greatly  in  appearance,  habits,  and  metamor- 
phoses from  those  of  the  most  closely  allied  families,  and  even  the  two  sexes 


Fig.  117. — Phylloxe'ra  vasta'trix:  a,  Sexed  stage  larvifonn  female,  the 
dark-colored  area  indicating  the  single  egg;  b,  egg,  showing  the  indistinct 
hexagonal  sculpturing;  c,  shriveled  female  after  oviposition;  d,  foot  of 
same;  e,  rudimentary  and  functionless  mouth  parts.     (Marlatt.) 


0- 


1'^    >1 


% 


/ 


^ 


Fig.  118. — Ladybird  feeding  on  scale  insects,  Pentil'ia  (Smilia)  misel'la: 
a,  beetle;  b,  larva;  c,  pupa;  d,  blossom  end  of  pear,  showing  scales  with 
larvae  and  pupie  of  Pentilia  feeding  on  them,  and  pupse  of  Pentilia  attached 
within  the  calyx;  all  enlarged.  (Howard  and  Marlatt,  Bull.  U.  S.  Dept. 
of  Agriculture.) 

of  the  same  species,  says  Comstock,  differ  greatly.     The  males,  unlike  all 
other  members  of  the  order,  undergo  a  complete  metamorphosis.    The  adult 


148  BRANCH    ARTHROPODA 

male  has  but  a  single  pair  of  wings  and  has  no  organs  for  procuring  food. 
The  mouth  parts  disappear  during  metamorphosis  and  a  second  pair  of 
eyes  develops.  The  adult  female  is  always  wingless  and  the  body  is  always 
scale-like  or  gall-like  in  form,  or  grub-like  and  clothed  with  wax.  Those 
of  some  species  retain  their  eyes,  antonnfr,  and  legs,  while  others  are  fixed 
in  adult  life  and  very  degenerate,  laikinii  eyes,  antennae,  wings,  and  legs. 
In  speaking  of  the  San  Jose  scale,  Kello^ij^  says,  "  it  has  a  long,  fine,  flexible 
process  projecting  from  near  the  center  of  its  under  side,  this  is  its  sucking 
proboscis,  and  serves  as  a  means  of  attachment  as  well  as  an  organ  of  feed- 
ing." The  San  Jose  scale  is  very  prolific.  It  was  ascertained  at  Washington 
that  there  are  four  regularly  developed  generations  and  possibly  part  of  a 
fifth  in  a  year.  It  is  estimated  that  about  200  females  (and  about  the  same 
number  of  males)  are  given  birth  to  by  each  female.  Thus  the  descendants 
of  a  female  amount  to  3,216,080,400  individuals.  From  this  it  can  easily 
be  seen  how  destructive  to  fruit  trees  this  pest  soon  becomes.  It  is  now 
found  in  every  state  and  territory  and  in  Canada.  Many  states  have 
laws  to  try  to  prevent  its  distribution  with  nursery  stock. 

Perhaps  the  most  effective  remedy  is  the  fumigation  of  orchard  trees  by 
hydrocyanic  gas.  To  do  this  the  tree  is  entirely  enclosed  in  a  large  tent 
and  the  gas  generated  under  it  "  by  pouring  about  50  ounces  of  water  into 
5  ounces  of  commercial  sulphuric  acid  and  dropping  into  it  15  ounces  of 
cyanid  of  potassium."  These  amounts  are  sufficient  for  a  tree  12  feet  high 
with  a  spread  of  10  feet.  The  fumes  are  deadly  -poison.  Of  sprays  for 
leaves  and  greenhouse  plants,  crude  petroleum  and  kerosene  emulsion  are 
best.  Protection  of  the  birds  is  one  great  means  of  holding  these  jiests  in 
check.  It  has  been  proved  by  the  examination  of  22(')  stonuiclis  that  more 
than  one-fifth  of  the  food  of  the  blackheaded  grosbeak  (Zuntilo'ilia  indano- 
ceph'ala^)  consists  of  scale  insects.  For  the  work  (Fig.  118)  of  ladybird 
beetles  see  p.  147. 

ORDER  VIII.      COLEOP'TERA 

This  order  consists  of  eleven  or  twelve  thousand  species  in 
America,  north  of  Mexico. 

The  mouth  parts  of  beetles  (Fig.  1 19)  consist  of  the  upper 
lip  or  lahrum,  the  jaws  or  mandibles  for  seizing  the  prey  or  for 
gnawing;  the  complicated  many  pieced  maxillce  with  usually 
prominent  maxillary  palpi;  the  lower  lip  or  labium  of  several 
parts,  and  rather  large  labial  palpi.  These  mouth  parts  are 
adapted  for  biting,  and  are  not  easy  for  beginners  to  identify. 
The  student  should  identify  these  parts  on  a  large  beetle  with 
the  help  of  a  good  figure  (Fig.  119)  and  a  good  magnifying 
glass. 

Compound  eyes  are  present,  but  usually  the  simple  eyes  are 
wanting. 

The  wings  are  four  in  number,  except  in  some  ground  beetles, 
which  have  only  the  anterior  pair.  The  anterior  wings  are 
1  Plate  III,  Bulletin  32,  U.  S.  Biological  Survey. 


COLEOPTERA 


149 


quite  rigid  and  meet  in  a  line  on  the  back,  forming  a  sheath  to 
inclose  the  membranous  posterior  wings,  which  fold  up  under 
the  fore  wings  or  elytra  when  not  in  use. 

The  body  is  usually  compact.  The  under  surface  of  the 
abdomen  is  hard,  but  the  upper  surface  beneath  the  elytra  is 
soft  and  yielding,  thus  permitting  respiration. 


Uh  'f 


Fig.  119. — Under  surface  of  Har'palus  caligin'osus:  a,  Ligula;  b,  para- 
glossa;  c,  supports  of  labial  palpi;  d,  labial  palpus;  e,  mentum;  /,  inner  lobe 
of  maxilla;  g,  outer  lobe  of  maxilla;  h,  maxillary  palpus;  i,  mandible;  k, 
buccal  opening;  I,  gula  or  throat;  m,  m,  buccal  sutures;  /(,  gular  suture; 
0,  prosternum;  p',  episternum  of  prothorax;  p,  epimeron  of  prothorax; 
q,  q',  q",  coxse;  r,  r',  r",  trochanters;  s,  s',  s",  femora  or  thighs;  t,  t',  i", 
tibiae;  v,  v^,  v^,  etc.,  ventral  abdominal  segments;  lo,  episterna  of  mesothorax 
(the  epimeron  is  just  behind  it);  .r,  mesosternum;  y,  episterna  of  meta- 
thorax;  y',  epimeron  of  metathorax;  z,  metasternum.     (After  Leconte.) 


The  Young. — The  metamorphosis  is  complete.  The  larvse 
are  usually  called  grubs.  (See  Fig.  120,  p.  150.)  Their  habitats 
vary  much.  Some  live  in  trees,  others,  as  the  larvse  of  the  tiger 
beetle,  burrow  in  the  gound,  and,  with  the  head  at  the  sur- 
face, watch  for  their  prey.     Their  food  varies  according  to  the 


150 


BRANCH    ARTHROPODA 


habitat.  The  burying  beetles  (Fig.  120)  {Necrdph'orus)  pro- 
vide food  for  their  young  by  burying  carrion,  as  a  dead  mouse  or 
bird.  When  it  is  covered  over  with  earth  the  female  lays  her 
eggs  upon  the  carcass.  They  soon  hatch  and  the  larvse  feed 
upon  the  food  thus  provided  for  them. 

The  food  of  the  adult  Coleop'tera  also  varies  much.  Some, 
as  the  ground  beetles  {Carab'idce),  are  predaceous.  Others,  as 
the  carrion  beetles,  feed  upon  decaying  animal  matter,  while 


.^^^^ 


h  'J 


^^w^ 


Fig.  120. —  Necroph'orus  burying  a  mouse,  and  larva.     (Landois.) 


others,  as  the  Colorado  potato  beetles,   are  voracious  plant 
feeders,  making  this  order  of  much  economic  importance. 

Other  familiar  examples  are  the  apple-tree  borers,  the 
wire- worms,  fruit  and  grain  weevils,  and  the  white  grubs  of  the 
June  beetles  (Fig.  121). 

The  tiger  beetles  (Cicindd'idcp)  are  usuall^^  of  a  beautiful  metallic  green 
or  bronze,  banded  or  spotted  with  yellow,  though  some  are  bh^ck,  while 
those  living  in  white  sand  are  exactly  the  color  of  the  sand.  They  are 
the  most  active  of  all  beetles,  running  and  flying  well.  They  may  be 
found  on  bright  warm  days  on  dusty  roads  or  along  the  banks  of  streams. 


COLEOPTERA 


151 


Comstock  says  they  remain  still  until  within  our  sight,  but  out  of  reach, 
and  then  "  like  a  flash  they  fly  up  and  away,  alighting  several  rods  ahead 
of  us,"  with  eyes  toward  us.  The  ugly  larvae  live  in  vertical  burrows 
about  a  foot  deep  on  beaten  paths  or  in  the  sand.  The  larva,  with  its  dirt- 
colored  head  which  is  bent  at  right  angles  to  its  lighter  colored  body,  plugs 
the  entrance  to  its  burrow,  and  with  its  wide-open  jaws  forms  a  li\ing 
trap  for  passing  inserts.  On  the  fifth  abdominal  segment  there  !.■<  a  hump 
bearing  two  hooks  curved  forward,  by  which  the  larva  holds  fast,  thus  pre- 
venting large  ]:)rey  from  dragging  it  out  of  its  burrow. 

The  ground  beetles  (Fig.  122)  {Carah'idoe)  are  probably  the  most  im- 
portant family  of  predaceous  insects,  though  a  few  species  are  vegetable 
feeders.  They  are  usually  dark  colored  and  nocturnal,  but  some  are  large 
and  brilliantly  colored,  and  the  wing  covers  are  generally  "  ornamented 
with  longitudinal  ridges  and  rows  of  punctures."  They  "hide  in  daytime 
under  stones  and  logs.     There  are  about  twelve  hundred  species  in  North 


Fig.  121.— June  beetles:  1,  Pupa;  2,  larva;  3,  4,  adult.     (Riley,  Report  of 
State  Entomologist  of  Missouri.) 

America  The  larvae  of  most  of  them  are  long  flattened  grubs,  with  bodv  of 
uniform  breadth  throughout,  protected  on  top  bv  horny  plates,  ending  In  a 
pair  of  conical  bristly  appendages.  ILsually  they  bury  themselves  just 
beneath  the  surface  and  feed  upon  insects  which  enter  the  ground  to 
pupate.  They  destroy  large  numbers  of  leaf-feeding  beetles  or  their 
larvae.  They  pupate  in  small  round  cells  in  the  soil,  from  which  the  adults 
push  their  way  out. 

The  caterpillar  hunter  (Caloso'ma  scruta'tor)  is  a  familiar  example  of  the 
ground  beetles  (Fig.  122).  Its  wing  covers  or  elytra  are  bright  green  or 
violet,  margined  with  reddish.  It  is  found  on  trees  at  dusk.  It  is  known  to 
chmb  trees  and  make  raids  upon  the  hairy  tent  caterpillar,  hence  it  is  a 
fnend.  Two  others  (Calosnmn  fngirjum  and  C.  calidum)  are  hunters  of  cut- 
worms and  canker-worms.  The  latter  is  sometimes  called  the  fiery  hunter, 
from  the  rows  of  reddish  pits  on  its  black  elytra. 

Another  one  {Agonod'erus  pal'lipcs)  feeds  upon  sprouting  corn. 


152 


BRANCH  ARTHROPODA 


The  carnivorous  water  beetles  (Dylic'idce),  of  which  there  are  three 
hundred  species,  are  found  everywhere  in  streams  and  ponds  (Fig.  123). 
They  vary  in  length  from  I  to  1 }  inches.    The  diving  beetle  projects  the  tip 


'^^:^ 


Fig.  122. — Ground  beetle  (Calosoma),  similar   to  C.  scrutator;   below,  a 
Carabus.     (Brehm.) 

of  its  abdomen  through  the  surface  film  to  breathe.      It  raises  the  elytra  a 
little,  and  the  air  which  is  caught  under  them  is  held  by  the  fine  hairs  on  the 


'^  y/p 


n 


Fig.  123. — Carnivorous  water  beetles.     (Brehm.) 

back,  where  the  spiracles  are  situated.  Thus,  it  carries  a  supply  of  air 
which  enables  it  to  breathe  under  water.  These  beetles  make  interesting 
aquarium  specimens. 


DIPTERA  153 

Platy-psyl'la  casto'ris  is  the  sole  representative  of  the  family  Platypsyl'lidce. 
This  queerly  shaped  beetle  lives  a  parasitic  life  upon  beavers.  It  is  wingless 
and  blind,  and  the  elytra  arc  rudimentary  and  short,  exposing  five  abdomi- 
nal segments.     Its  degeneration  is  due  to  its  parasitic  life. 

The  lady-bugs  {Coccin<i'liil(v)  are  interesting  little  predaceous  beetles, 
yellow  or  reddish,  with  black  spots.  The  cottony  cushion-scale  {Ice'rya 
purchasi),  so  destructive  to  California  fruits,  was  subdued  by  a  lady-bug 
{Veda'lia  cardind'lis)  brought  from  Australia  to  feed  upon  it.  The  hop 
louse  is  destroyed  by  the  larvae  of  certain  lady-bugs  known  as  "  niggers." 
The  lady-bugs,  with  few  exceptions,  are  predaceous.  One  {Epilach'na 
horea'lis)  is  herbivorous.  Its  larva,  which  is  yellow  and  clothed  with 
forked  spines,  feeds  upon  the  leaves  of  the  squash  family. 

The  little  carpet  beetle  {Anthrc'nus  scrophida'rice)  is  a  household  pest. 
Its  larva  feeds  upon  carpets,  furs,  feathers,  and  woolens. 

The  fireflies  {Lampyr'idoe)  or  "  lightning-bugs  "  are  not  flies,  but  beetles. 
The  light  giving  has  never  been  fully  explained.  "  The  light-giving  organ 
is  usually  situated  just  inside  of  the  ventral  wall  of  the  last  segments  of  the 
abdomen,  and  consists  of  a  special  mass  of  adipose  tissue  richly  supplied 
with  air-tubes  (tracheie)  and  nerves.  From  a  stimulus  conveyed  by  these 
special  nerves  oxygen,  brought  by  the  network  of  tracheae,  is  released,  to 
unite  with  some  substance  of  the  adipose  tissue,  a  slow  combustion  thus 
taking  place.  To  this  the  light  is  due,  and  the  relation  of  the  intensity  or 
the  amount  of  light  1o  the  amount  of  matter  used  up  to  produce  it  is  the 
most  nearly  ix'rfcct  known  to  physicists. "^ 

Myrmecoph'ilous  Beetles. — There  are  nearly  one  thousand  species 
of  beetles  which  live  in  the  nests  of  ants.  Many  of  them  are  commensal 
with  the  ants,  deriving  perhaps  the  greater  benefit  by  the  association,  but 
others  live  truly  symbiotically  with  their  hosts.^  They  secrete  a  sweet 
substance  which  is  eaten  by  the  ants,  which  in  return  shelter,  clean,  and, 
by  regurgitation,  feed  them.  They  are  strangely  modified  for  this  mode 
of  life,  usually  by  degeneration. 


ORDER  IX.      DIP'tERA 

This  order  contains  al)out  fifty  thousand  species,  of  which 
about  seven  thousand  are  known  in  America.  It  includes  some 
famous  flies  (Fig.  124). 

The  mouth  'parts  are  adapted  for  piercing  and  sucking  or  for 
lapping.  Just  what  constitutes  these  mouth  parts  is  a  contro- 
verted question  among  scientists.  Comstock  says,  ''According 
to  the  most  generally  accepted  view  the  six  bristles  represent 
the  upper  lip  (lahrum),  the  tongue  {hijpopharynx) ,  the  two 
mandibles,  and  the  two  maxillae,  and  the  sheath  enclosing  these 
bristles  is  the  lower  lip  (labium)."  Identify  these  parts  on  the 
head  of  a  big  fly  with  the  aid  of  a  large  figure  and  a  magnifying 
glass. 

1  Kellogg,  p.  269.  2  Kellogg,  p.  553. 


154 


BRANCH    ARTHROPODA 


The  Wings. — As  the  ordinal  name  indicates,  these  insects 
have  two  membranous  wings.  No  fly  has  more  than  two 
wings  and  only  a  few  are  wingless.  They  have,  however, 
vestiges  of  a  second  pair,  called  halte'res  or  balancers,  ending  in 
short  knobs.  They  are  used  in  directing  the  flight  and  are  be- 
lieved by  some  to  be  auditory  organs. 

Family  Mus'cidae. — The  common  house-fly  (Mus'ca  domes' lica)  is  too  well 
known  for  our  comfort.  It  hibernates.  One  will  recall  having  seen  flies 
about  the  house  during  the  winter.     They  breed  about  stables  in  the  sum- 


Fig.  124. — Typhoid  fever  or  house-fly  {Mus'ca  domes' lica):  a,  Adult  male; 
b,  proboscis  and  palpus  of  same;  c,  terminal  joints  of  antennae;  d,  head  of 
female;  e,  puparium;  /,  anterior  spiracle;  all  enlarged.  (Howard  and 
Marlatt,  Bull.  U.  S.  Dept.  of  Agriculture,  1896.) 


mer.  The  eggs,  numbering  about  one  hundred,  hatch  in  about  twenty- 
four  hours.  The  soft,  white,  cylindric,  footless  larva  is  called  a  maggot. 
It  feeds  and  grows  for  about  a  week,  molting  twice,  and  then  pupates 
within  the  larval  skin,  or  -pupariuvi,  for  another  week.  It  then  makes  a 
circular  opening  in  the  puparium  and  emerges  as  the  adult  fly,  thus  giving 
time  for  a  numlaer  of  generations.  In  a  summer  the  offspring  of  a  single 
fly  may  reach  incredible  numbers.  It  is  now  known  that  the  principal  in- 
sect agent  in  the  spread  of  typhoid  fever  is  the  common  house-fly,  and 
great  care  should  be  taken  to  prevent  its  breeding.  All  human  and  horse 
excreta  should  be  kept  in  fly-tight  vaults  and  sprinkled  with  chlorid  of 
lime  or  quick  lime  at  least  once  a  week,  unless  wanted  for  fertilizing 
purposes.     All  garbage  cans  and  swill  pails  should  be  kept  covered,  and 


DIPTERA 


155 


sprinkled  with  lime  when  emptied.  Chicken  pens  should  be  cleaned  often 
and  sprinkled  with  lime. 

The  iiuuiy  little  projections  on  the  feet  of  the  fly  are  tubular,  and  secrete 
a  sticky  fluid  which  enal)lcs  it  to  walk  upside  down. 

The  bloiv-Jly  and  the  jh^h-fly,  close  relatives  of  the  house-fly,  lay  their 
eggs  upon  meat,  cheese,  and  other  provisions  or  upon  decaying  animal  sub- 


Fig.  125. — An  adult  mosquito,  much  enlarged,  with  all  the  parts  that  are 
used  in  classification  named.  (Smith,  N.  J.  Experiment  Station,  Bulletin 
171,  1904.) 


stance,  on  which  the  maggots  feed.  Thus,  while  a  great  annoyance,  they 
may  do  some  good  by  acting  as  scavengers.  The  most  common  flesh-fly 
is  perhaps  Sarcoph'aga  sarrace'niw,  which  resembles  a  large  house-fly.  It 
furnishes  another  example  of  viviparous  insects;  in  other  words,  the  larvse 
are  brought  forth  alive. 


156  BRANCH    ARTHROPODA 

Horse-flies  (Taban'idce)  are  also  pests  of  man  and  beast.  They  are 
most  abundant  in  the  hot  summer  days.  The  large  black-bodied  horse- 
flies, of  which  there  are  a  hundred  species,  belong  to  the  genus  Tabanus. 

The  Bot-flies  {CE'stridce). — "  The  horse  bot-fly  {Gastrdph'ilus  e'qui)  closely 
resembles  the  honey-bee  in  form,  except  that  the  female  has  an  elongated 
abdomen  curved  under  the  body."  Horses  have  an  instinctive  fear  of  this 
fly.  It  attaches  its  eggs  to  the  hair  of  the  legs  and  shoulders  of  the  horse, 
and  they  are  taken  into  the  mouth  by  biliiiji  the  irritated  jjlaco.  The 
larvae  fasten  themselves  to  the  lining  of  the  .stoinach.  When  >i;ro\vn,  during 
the  fall  and  winter,  they  pass  out  and  develop  within  a  i>uparium. 

The  larvse  of  Bot-flies  of  cattle  or  oxwarhles  {Hypoder'ma  linea'ta)  live 
just  beneath  the  skin  on  the  backs  of  cattle,  which  are  made  frantic  by  their 
burrowing. 

The  sJieej)  bot-fly  deposits  its  larvae  in  the  nostrils  of  sheep,  antelope,  etc. 
They  work  up  into  the  frontal  sinuses  and  horns  and  cause  the  "  staggers."' 

Reindeer,  deer,  rabbits,  and  squirrels  are  infested  by  larvae  of  species  of 
bot-flies,  and  one  or  two  species  infest  man. 


Fig.  126. — 1,  Egg-mass  of  the  common  mosquito;  2,  larva  breathing 
at  the  surface  of  the  water;  3,  a  pupal  mosquito.  (From  Hampton 
Leaflet.) 

Mosquitoes  (Culic'idae)  (Fig.  125)  seem  too  well  known  to  need  descrip- 
tion, but  there  are  other  insects  so  similar  that  they  are  often  mistaken  for 
them.  Comstock  says  "  the  most  distinctive  feature  of  mosquitoes  is  the 
fringe  of  scale-like  hair  on  the  margin  of  the  wing  and  also  on  all  known 
American  forms  on  each  of  the  wing  veins."  The  males  differ  from  the  females 
in  having  feathery  antennae  and  in  the  absence  of  the  piercing  stylets.  As 
a  rule  they  do  not  sing  or  bite,  and  probably  feed  upon  the  juices  of  plants, 
as  do  the  females  if  they  cannot  "  get  blood."  The  larvae  (Fig.  126),  called 
"  wrigglers  "  or  "  wiggle-tails,"  are  too  often  found  near  our  dwellings  in 
rain-barrels,  slop-pails,  open  cisterns,  open  sewers,  water  troughs,  lily-tubs, 
ponds,  anywhere  where  the  water  is  allowed  to  remain  long  enough  for  their 
development,  which  requires  from  eight  to  eighteen  days.  Of  the  three 
principal  genera,  Cillex  contains  most  of  our  mosquitoes  whose  bite  and  song 
are  well  known.  Anoph'eles  is  the  genus  which  is  the  intermediate  host 
and  the  transmitter  of  the  malaria  germ.     Of  course  it  cannot  transmit 

1  Comstock,  p.  478;  Hertwig,  p.  493. 


DIPTERA 


157 


these  germs  unless  it  has  been  infected  with  them  itself.  Stegom'yia 
fascia' t a  (Fig.  127)  is  the  yellow-fever-carrying  species,  so  much  dreaded  in 
our  southern  states.  It  has  been 
ostablishcil  by  observation  and  ex- 
periment '  t  hat  these  mosquitoes,  if 
they  have  bitten  persons  affected  by 
malaria  or  yellow  fever,  actually 
carry  these  diseases,  also  that  Steg- 
omyia  fascia' ta  and  Cu'lex  fati'gans, 
var.  skusii,  and  Anoph'eles  rossii 
carry  certain  forms  of  filariasis. 
These  organisms  belong  to  the 
round  worms  or  Nematoda  (see 
p.  41).  The  most  common  form  of 
filariasis  is  elephantiasis.  In  this 
disease  the  legs  and  arms  are  af- 
fected. One  leg  may  become  so 
enlarged  as  to  weigh  as  much  as 
the  rest  of  the  body,  or  the  arm 
may  become  a  foot  thick  and  horri- 
bly repulsive.  In  Samoa,  says  Kel- 
logg, fully  one-third  of  the  natives 
are  attacked  by  this  incurable  dis- 
ease, which,  though  slow  and  almost 
painless,  is  certainly  fatal.  Ma- 
laria, so  widespread  in  the  United 
States,  becomes  even  more  prevalent  and  more  often  fatal  in  the  tropics. 
Millions  die  from  it  every  year.  In  a  single  year  five  million  persons  died 
of  malaria  in  India  alone.  Hence  the  mosquito  is  to  be  classed  not  sim- 
ply as  a  great  annoyance,  but  as  an  insidious  foe  to  health  and  life. 


Fig.  127. — Stegom'yia  fasci'ata  (en- 
larged). (Howard,  Bull.  U.  S.  Dept. 
of  Agriculture,  1902.) 


Fig.  128. — The  common  harmless  Fig.  129. — The  malarial  mosquito 

mosquito  stands  this  way  on  a  ver-  stands  with  its  head  pointing  down- 
tical  or  horizontal  svu-face.  (From  ward  at  an  angle  of  from  20  to  30 
Hampton  Leaflet.)  degrees  from  a  vertical  or  horizontal 

surface.     (From  Hampton  Leaflet.) 

The  common  mosquito,  Culex  (Fig.  128),  maybe  distinguished  from  the 
malaria-carrying  form  (Fig.  129)  in  several  ways.    The  female  Culex  has 

1  Kellogg,  pp.  617,  630. 


158 


BRANCH  ARTHROPODA 


short  palpi,  while  the  Anoph'eles  has  palpi  nearly  as  long  as  the  beak,  making 
three  long  projections  on  the  head.  It  may  be  distinguished  also  by  the 
way  it  alights.  The  Culex  is  "  hump-backed  "  with  the  beak  pointing  down- 
ward, while  in  the  Anopheles  the  body  and  beak  lie  in  the  same  plane.  The 
eggs  of  Culex  are  laid  in  a  boat -shaped  mass,  while  the  eggs  of  Anopheles 
are  laid  "  singly  and  at  random,"  but  run  together,  forming  irregular  groups 
or  strings.  The  larva  of  Culex  hangs  with  the  head  down,  so  as  to  keep  the 
end  of  the  respiratory  tube,  which  is  borne  by  the  next  to  the  last  somite,  in 
contact  with  the  air.  The  larval  stage  lasts  about  five  or  six  days  or  longer 
in  unfavorable  conditions.     The  larva  of  Anopheles  has  a  very  short  respi- 


Fig.  130. — A  fine  breeding-place 


siiuitoes.     (Hampton  Leaflet.) 


ratory  tube,  and  consequently  lies  in  a  horizontal  position  just  under  the 
surface  film  in  order  to  obtain  air.  (This  explains  how  it  is  that  kerosene 
oil  "  poured  upon  the  troubled  waters  "  destroys  the  larvse.  They  are 
simply  drowned  or  suffocated  as  the  surface  film  of  oil  excludes  the  air.) 
The  larval  stage  lasts  from  twelve  to  fourteen  days. 

The  mosquito  larva,  after  growing  several  days  and  molting  twice,  changes 
into  a  club-shaped  pupa  (Fig.  126)',  the  head  and  thorax  being  greatly  en- 
larged, while  the  abdomen  is  slender.  At  the  caudal  end  is  a  pair  of  leaf- 
like locomotor  or  swimming  appendages.  It  takes  no  food,  and  when  un- 
disturbed it  floats  upon  the  water,  but  when  disturbed  it  is  active,  thus  differ- 


DIPTERA  159 

ing  from  the  pupal  stage  of  most  insects.  The  pupa  of  Anopheles  has  a 
narrower  and  more  pointed  head  and  much  shorter  and  wider  breathing 
tubes  than  those  of  Cidcx. 

Mosquitoi's  flourish  aHke  in  the  heated  moist  regions  of  the  tropics  and 
in  the  frigid  regions  of  ice  and  snow.  Many  species  have  their  haunts  and 
breeding -places  in  fresh  water,  others  breed  abundantly  and  some  perhaps 
exclusively  in  brackish  water.  They  are  found  even  in  arid  regions  far 
from  water,  where  it  is  probable  they  lay  their  eggs  in  the  ground.  So, 
go  where  we  will,  we  cannot  escape  them,  we  must  fight  them. 


Fig.  131. — Wheat  plant,  showing  injuries  by  Hessian  fly:  a.  Egg  of  Hes- 
sian fly;  b,  larva;  c,  flaxseed;  d,  pupa  or  chrysalis;  e,  female,  natural  size; 
/,  female;  g,  male;  h,  flaxseed  or  pupal  stage  between  the  leaves  and  stalk; 
i,  chalcidid  parasite;  all  enlarged  except  wheat  stem  and  f.  (After  Riley, 
Burgess,  and  Trouvelot.) 

A  very  easy  and  successful  way  of  getting  rid  of  mosquitoes  in  a  pond 
which  will  sustain  fish  is  to  stock  it  with  such  fish  as  the  "  top-minnow," 
sun-fish,  and  stickleback,  whose  young  csixM'ially  feed  upon  the  larvae. 
Dragon-flies  also  should  be  encouraged  and  protected,  since  their  nymphs 
feed  upon  the  larv;^  of  mosquitoes,  and  the  adults  are  voracious  feeders 
upon  the  mosquitoes.  In  fact,  if  it  were  not  for  the  dragon-flies,  life  in  the 
Hawaian  Islands  would  be  almost  intolerable  on  account  of  the  hordes  of 
mosquitoes.    Pools  and  marshes  should  be  drained,  or,  if  the  pool  or  mud- 


160 


BRANCH  ARTHROPODA 


puddle  is  small,  it  may  be  filled  up  with  less  expense.  If  neither  can  be 
done,  then  spraying  with  kerosene  along  the  edges  of  the  banks  and  the 
surface  of  the  water  every  two  or  three  weeks  should  be  resorted  to.  The 
oil  kills  by  contact  many  adults  and  larvse  among  the  grass  and  weeds,  and 
by  coating  the  surface  of  the  water  with  a  film  of  oil  the  "  wiggle-tails  " 
are  suffocated.  Many  females  also  are  killed  by  this  film  of  oil  when  they 
return  to  the  surface  to  deposit  their  eggs.  All  open  barrels  (Fig.  130) 
and  cisterns  should  be  screened,  so  that  the  female  mosquito  cannot  get  to 
the  water  to  deposit  her  eggs. 

The  gall-gnats  (Cccidomyi'idoe)  are  the  smallest  flies,  but  their  great  num- 
bers and  their  gall-forming  habits  make  them  great  enemies  of  plants. 
There  are  about  a  hundred  species  in  the  United  States,  most  of  which  are 


•J)lPTEf\f<- 


■ytV^ENOPfERfK- 


\/oLuc£LLf 


Vespp.    Vulgaris. 


Vol  .    Bomb  /LArJs, 


BOMBUS     LAOIJiARlJs. 


Fig.  132. — Two  cases  of  mimicry:  flies  resembling  a  wasp  in  the  one,  and  a 
bee  in  the  other.     (Romanes.) 


destructive  to  cultivated  plants.  The  minute  reddish  or  white  eggs  are 
deposited  on  or  in  living  plants,  and  the  maggot-like  larvie  probably  imbibe 
their  food  through  the  skin. 

The  Hessian  fly  belongs  to  this  family.  It  is  a  tiny  blackish  midge  which 
lays  its  cjrirs  (Fi^.  131)  in  the  sheaths  of  leaves  some  distance  from  the 
ground.  The  larva  lives  between  the  base  of  the  leaf  and  the  main  stalk 
and  feeds  upon  the  sap  of  the  growing  wheat.  There  are  four  or  five  broods 
a  year,  both  spring  and  winter  wheat  being  infested.  It  is  estimated  that 
the  ravages  of  this  insect  cost  the  farmers  of  this  country  $10,000,000 
annually.  Were  it  not  for  its  natural  enemies,  a  half-dozen  hymenop- 
terous  parasites,  it  would  soon  take  the  whole  crop  of  wheat,  rye,  and 
barley.     The  chief  remedies  which  the  farmer  can  use  are  the  late  planting 


SIPHONAPTERA  161 

of  winter  wheat ;  the  burning  or  plowing  of  stubble ;  the  early  planting  of 
strips  of  decoy  wheat  to  attract  the  egg-laying  females  to  deposit  their  eggs, 
and  then  to  be  burned;  and  the  rotation  of  crops. ^ 

Another  common  and  conspicuous  gall-gnat  is  the  pine-cone-willow  gall- 
gnat,  which  lays  its  eggs  in  the  newly  formed  buds  of  the  willow.  The 
stem  ceases  to  grow,  but  the  leaves  continue,  causing  the  bud  to  resemble  a 
pine-cone.  In  this  the  larva  remains  through  the  summer  and  winter, 
pupating  in  early  spring,  soon  after  which  the  adult  emerges.  There  are  a 
number  of  others,  as  the  clover-leaf  midge,  the  clover-seed  midge,  and  the 
wheat  midge,  each  injurious  to  its  respective  crop. 

The  Syrphus  flies  [Sijr' phidoe),  of  which  there  are  twenty-five  hundred 
species,  differ  much.  Some  species  in  the  adult  form  imitate  bees  and 
wasps  (Fig.  132).  They  can  be  distinguished  by  the  longitudinal  "spu- 
rious "  vein  between  veins  three  and  five.  Some  of  the  larva;  are  found  in 
ants'  nests  and  some  in  the  nests  of  bumble-bees  and  wasps.  One  of  the 
commonest  is  the  yellow-banded  species  of  the  genus  Syrphus,  whose  larvae 
do  great  good  by  destroying  aphids,  in  whose  colonies  they  live. 

The  larvae  of  one  of  the  bee-flies  {Bombyli'ida)  are  also  friends  of  man. 
They  destroy  many  grasshoppers  by  burrowing  into  the  egg-cases  and 
devouring  the  eggs.  The  adults  of  these  maggot-like  larvae  are  swift, 
hairy,  and  bee-like,  mimicking  the  bee  in  appearance  and  feeding  habits. 

ORDER   X.      SIPHONAPTERA 

The  fleas  consist  of  a  single  family,  the  PuUc'idce,  of  nearly 
one  hundred  and  fifty  species,  about  fifty  of  which  are  found  in 
the  United  States.  Until  recently  the  fleas  were  regarded  as 
degenerate  wingless  Diptera,  but  entomologists  now  place 
them  in  a  separate  order.  They  are  found  usually  as  temporary 
external  parasites  on  the  cat,  rat,  rabbit,  dog,  poultry,  and 
man. 

The  mouth  parts  are  adapted  for  piercing  and  sucking. 
They  are  almost  wingless,  the  wings  being  represented  by  mere 
scaly  plates.  The  bodies  are  naked,  smooth,  hard,  oval,  and 
compressed.  The  metamorphosis  is  complete  (Fig.  133). 
The  "  small,  slender,  white,  footless,  worm-like  grubs  "  are 
composed  of  thirteen  segments.  They  seem  to  live  on  dry  dust 
and  the  organic  matter  it  contains.  When  grown  they  usually 
spin  a  silken  cocoon  and  pupate  in  the  dust.  In  the  species 
infesting  cats  and  dogs  the  larval  life  lasts  only  about  a  week. 
The  development  from  the  egg  to  the  adult  requires  but  two 
weeks.  Fresh  pyrethrum  dusted  about  the  rugs  where  dogs 
and  cats  lie,  or  spraying  the  rugs  with  formalin,  will  help  get 
rid  of  fleas. 

1  Jackson  and  Daughterty's  "  Agriculture  through  the  Laboratory  and 
School  Garden." 


162 


BRANCH    ARTHROPODA 


The  chig'oe,  a  small  flea  of  the  West  Indies  and  of  South  America,  often 
causes  serious  trouble  by  burrowing  under  the  toe-nail  or  the  skin  of  the  foot 
of  man.  The  female  burrows  under  the  skin,  becomes  encysted  and  dis- 
tended by  the  eggs  which  hatch  here,  and  unless  the  young  are  carried  out 
by  the  pus  they  probably  develop  here. 


Fig.  133. — Common  cat  and  dog  flea  {Pu'lex  serrtit'iceps) :  a,  Eggs;  b, 
larva  in  cocoon;  c,  pupa;  d,  adult;  e,  mouth  parts  of  same  from  side;  /, 
labium  of  same  from  below;  g,  antenna  of  same;  all  much  enlarged.  (How- 
ard, Bull.  U.  S.  Dept.  of  Agriculture,  1896.) 

Rat  Fleas. — It  is  believed  that  in  tropical  countries  the  disease  germs 
of  the  bubonic  plague  may  be  transmitted  from  rats  to  men  by  the  bites  or 
punctures  of  rat  fleas. 


ORDER    XI.      LEPIDOP'TERA 

This  order  includes  such  common  insects  as  butterflies  and 
moths  or  "  millers."  There  are  more  than  6600  species  in 
North  America. 

The  head  is  rather  small  for  the  size  of  the  ])ody. 

The  mouth  parts  are  highly  complex,  a  striking  example  of 
adaptation  of  structure  to  function.  The  two  maxillae  are  greatly 
modified  into  a  long  hollow  tul^e  (Fig.  141)  for  sucking  the  juices 
of  fruits  or  the  nectar  of  flowers.  When  not  in  use  this  tube, 
tongue,  or  proboscis  is  coiled  up  between  two  projections,  the 
labial  palpi.  Many  moths  do  not  feed  in  the  adult  stage  and 
the  maxillae  are  lacking.     The  other  mouth  parts  are  mere 


LEPIDOPTERA  163 

rudiments.  Find  these  rudiments  on  a  large  specimen  and 
compare  with  the  mouth  parts  of  the  grasshopper. 

The  compound  eyes  are  large  and  conspicuous. 

Some  of  the  Lepidoptera  have  ocelli,^  one  on  either  side  above 
and  near  the  margin  of  these  compound  eyes,  but  they  are  usually 
hidden  by  the  scales  covering  the  head. 

The  many  jointed  antennse  are  very  various  in  size,  shape,  and 
color. 

The  thorax  bears  three  pairs  of  legs  and  two  pairs  of  wings. 
The  wings  are  large,  membranous,  and  covered  with  overlapping 
scales,  which  are,  in  reality,  modified  hairs.  These  scales 
strengthen  the  wings  and  give  coloration  to  the  species. 

The  ahdo77ien  has  no  paired  appendages. 

The  metamorphosis  is  complete.  The  larvae  of  Lepidoptera 
are  commonly  called  caterpillars.  They  are  very  destructive, 
being  almost  without  exception  injurious  to  vegetation.  Com- 
stock  says,  "a  very  few  feed  upon  plants  below  the  surface  of 
the  water."  The  species  which  destroys  scale-bugs,  also  those 
attacking  woolen  cloth,  feed  upon  animal  matter.  Caterpillars 
are  usually  cylindric.  The  thorax  bears  six  clawed,  jointed, 
tapering  legs,  which  develop  into  the  legs  of  the  adult.  The  ab- 
domen bears  from  two  to  ten  thick,  fleshy,  non-jointed,  contrac- 
tile pro-legs  (see  figure  of  silkworm,  ]).  126),  which  are  shed  at 
the  last  molt.  The  pro-legs  are  usually  surrounded  at  the  ex- 
tremity by  many  minute  hooks.  The  mouth  parts  of  caterpil- 
lars are  formed  for  biting,  hence  they  can  be  exterminated  by 
the  arsenical  poisons  when  it  is  safe  to  use  them. 

The  Lepidoptera  pupate  in  chrysalids  or  cocoons.  The 
adult  stage  is  the  familiar  winged  form.  It  does  no  harm  except 
the  occasional  puncturing  of  fruit  to  get  the  juice. 

Distinctions  Between  Butterflies  and  Moths. — The  antennse  of 
butterflies  are  filiform  or  thread-like  for  most  of  their  leng-th,  but 
the  end  is  thickened  into  a  spindle-shaped  enlargement  or  club. 
The  antennse  of  moths  are  of  various  forms,  usually  filiform  or 
pectinate  (feathery),  but  never  clubbed.  Butterflies  are  diurnal, 
while  the  moths  are  crepuscular  or  nocturnal.  Butterflies 
at  rest  fold  the  wings  together  in  a  vertical  position  above  the 
back.  Moths  spread  the  wings  horizontally,  or  fold  them  leaf- 
1  Comstock,  p.  199. 


164  BRANCH   ARTHROPODA 

like,  or  wrap  them  about  the  body,  but  never  hold  them  in  a 
vertical  position. 

The  skipper  butterflies  are  diurnal,  but,  unlike  other  butter- 
flies, the  antennae  are  usually  recurved,  forming  hooks.  Their 
bodies  are  more  robust  than  those  of  other  butterflies.  They 
fold  the  wings,  sometimes  only  the  front  ones,  vertically  when 
at  rest.  The  skipper  caterpillars  are  distinguished  from  other 
caterpillars  by  the  unusually  large  head  and  the  much  constricted 
neck.     Skippers  spin  thin  cocoons  of  silk  in  which  to  pupate. 

Authorities  enumerate  650  species  of  butterflies  in  the  United 
States  east  of  the  Mississippi  River.  Kellogg  gives  six  families  of 
butterflies  and  forty-four  of  moths.  Of  the  thousands  of  species 
with  their  various  and  interesting  habits  only  a  few  can  be 
mentioned.  These  should  serve  to  stimulate  the  student  to 
observe  and  study  others.  See  "  Laboratory  and  Field  Guide  " 
for  collecting,  breeding,  and  mounting. 

The  carpenter  moths  (Cos  'sidce) ,  of  which  there  are  twenty  species  in  North 
America,  are,  in  the  larval  stage,  wood-borers,  burrowing  about  in  the  heart- 
wood  of  shade  and  fruit  trees.  Pepper  and  salt  gray  moths,  indistinctly  or, 
in  a  few  cases,  conspicuou.sly  marked  with  black  and  white,  lay  their  eggs 
on  the  bark  of  trees,  where  the  naked,  grub-like  larvae  burrow  into  the  wood. 
Here  they  tunnel  through  the  wood  for  two  to  four  years,  according  to  the 
species.  In  this  tunnel  the  pupal  stage  is  spent.  When  ready  for  the  adult 
stage  the  pupa  works  its  way,  by  backward  projecting  saw-like  teeth  on  the 
abdomen,  to  the  opening  of  the  tunnel,  from  which  the  moth  emerges. 
The  empty  pupa  skins  may  often  be  found  projecting  from  the  deserted 
burrows. 

The  meal  moth  (Pyr'alis  fnrina'lis),  whose  larva  feeds  upon  meal,  flour, 
or  old  clover-hay,  is  a  common  species.  It  is  usually  found  near  the  larva 
food,  but  sometimes  sits  upon  the  ceiling  with  its  tail  curved  over  its  back. 
Its  expanse  of  wing  is  about  an  inch.  The  wings  are  light  brown  with  red- 
dish reflections  and  a  few  wavy  transverse  lines.  The  larva  makes  long 
tubes  of  silk  in  the  meal.  Perhaps  the  most  formidable  mill  pest  is  the 
Mediterranean  flour  moth  {Ephrs'tia  kuchnvi'la).  The  caterpillars  spin 
silken  galleries  through  which  they  ])ass,  making  the  flour  lumpy  and  stringy. 

The  coccid-eating  pyralid  (Lcelil'ia  coccidiv'ora)  differs  from  other 
members  of  its  family  in  being  predaceous.  It  feeds  upon  the  eggs  and 
young  of  several  scale  insects.  The  larva  spins  a  silken  tube  or  bag,  in 
which  it  lives. 

The  codling  moth  {Carpocap'sa  pomonel'la)  (Fig.  134)  is  one  of  the  best- 
known  and  most  cordially  hated  of  moths.  It  causes  an  annual  loss  in  the 
United  States  of  .$10,000,000.  The  adult  is  small,  with  finely  mottled,  ash- 
gray  or  rosy  fore  wings.  Near  the  square  ends  of  these  wings  is  a  large  brown- 
ish spot  marked  with  met  allic,  bronze  bands.  The  hind  wings  and  abdomen 
are  a  lustrous  light  yellow  isli  brown.  This  moth  lays  its  eggs  singly  in  the 
blossom  end  of  an  apple,  just  when  the  petals  fall.     When  the  larva  hatches 


LEPIDOPTERA 


165 


it  eats  its  way  into  the  core.  The  affected  fruit  usually  falls  to  the  ground 
before  ripening.  The  full-grown  larva  burrows  out  of  the  apple  and 
pupates  in  a  cocoon  under  the  rough  bark  of  a  tree.  After  two  weeks  in  the 
pupal  stage  the  adult  of  the  first  brood  emerges  and  lays  its  eggs  on  later 
apples.  The  larvis  are  carried  into  the  cellar  with  the  fall  and  winter  ap- 
ples, pupate  in  the  crevices  of  the  barrels  or  boxes,  and  remain  till  the  fol- 
lowing apple-blossom  time.  Spraying  the  fruit  with  Paris  green  soon  after 
the  petals  fall  and  again  in  about  two  weeks  will  greatly  reduce  the  loss. 
At  this  time  the  fruit  stands  with  the  blossom  end  up  and  the  poison  will 
then  reach  the  place  where  the  larva  hatches. "^  The  larva  does  not  remain 
long  in  tlie  :ii)i)le  after  it  falls  to  the  ground.  Hence  if  the  apples  are  burned 
or  fed  to  hogs  at  once  the  larvaj  will  be  destroyed. 


Fig.  134. — The  codling  moth:  a,  Apple  showing  burrow;  b,  place  where 
the  worm  entered;  d,  chrysalis  or  pupa;  e,  larva  or  worm;  /,  moth  with 
wings  closed;  g,  moth  with  wings  spread;  h,  head  end  of  larva;  i,  cocoon 
in  which  the  larva  changes  to  a  chrysalis.  All  about  life  size  except  h. 
(Riley.) 


The  geometrids  ai'e  of  interest  because  of  the  peculiar  phase  of  protec- 
tive resemblance  possessed  by  their  larva?.  They  cling  by  their  posterior 
legs  to  the  branches  of  trees  or  other  plants,  and,  holding  the  body  out 
straight,  stiff,  and  still,  look,  for  all  the  world,  like  short,  stubby  branches. 
My  little  (laughter  searched  for  fully  five  minutes  within  a  few  inches  of  a 
green  si)e(iiiion  on  a  sweet-pea  vine  before  discovering  it.  When  disturbed 
th(>  caterpillar  swings  down  by  a  silken  cord  till  it  reaches  the  ground.  Most 
of  them  are  leaf  eating  and  they  are  sometimes  so  numerous  as  to  do  great 
injury.  Among  them  are  the  canker-worms  (Fig.  135),  currant  span- 
worms,  two  or  three  species  which  feed  ui)on  the  grape,  and  the  raspberry 
geometrid.  They  maybe  i)ois()ne(l  by  Paris  green,  since  all  insects  with 
biting  mouth  parts  can  be  killed  by  poisoning  the  food  with  arsenical 
sprays. 

1  Jackson  and  Daugherty's  "  Agriculture,"  p.  321. 


166 


BRANCH  ARTHROPODA 


The  owlet  moths  (Noctu'ida;),  of  which  there  are  more  than  twenty-five 
hundred  species  in  America,  fly  at  night  and  are  familiar  visitors  around  our 


Fig.  135. — The  spring  canker-worm:  a,  Egg  mass,  natural  size;  b,  egg,  mag- 
nified; c,  larva;  d,  female  moth;  e,  male  moth.     (Riley.) 

evening  lights.     To  these  belong  the  numerous  cut-worm  moths  and 'army 
moths.     Most  of  this  large  family  are  inconscipuous  and  dull  colored,  but 


Fig.  136. — The  boll-worm  or  corn-ear-worm.     (Riley.) 

the  group  of   "  underwings,"   or  Catoc'alas,  are  exceptions  to  this  rule. 
Strangely  enough  it  is  their  posterior  or  under  wings  which  are  conspicu- 


LEPIDOPTERA 


167 


ously  colored  and  banded.  When  at  rest  the  incongpicuously  marked 
dull-colored  fore  wings  completely  cover  the  hind  wings.  During  the  day 
the  moths  rest  close  against  the  bark  of  tree  trunks,  where  it  is  almost  im- 
possible to  distinguish  them.  Collectors  smear  syrup  on  the  trunks  of 
trees  where  no  sweet-smelling  flowers  are  near,  and  collect  the  insects  thus 
enticed  on  a  dark,  damp  night,  with  a  dark-lantern  and  wide-mouthed 
bottles. 

The  cotton  worm  {Alv'tia  argilWcea)  also  belongs  to  this  family.  It 
feeds  upon  the  leaves  of  the  cotton  plants.  The  cotton  boll-worm  (Helio'- 
this  arnug'era)  (Fig.  136)  feeds  upon  the  pods  or  bolls.  The  destruction 
caused  by  these  two  caterpillars  causes  an  annual  loss  of  millions  of  dollars 


W  1  / 
1/ 


mil 


Fig.  137. — Corn-worm  eating  an  ear  of  corn.     (Quaintance,  F.  B.  191, 
B.  Ent.  U.  S.  D.  A.) 


to  the  cotton  growers.  The  boll-worm  has  become  a  great  pest  in  the 
north  also  as  the  corn-ear-worm  (Fig.  137).  Just  at  the  roasting  ear 
stage  it  eats  the  juicy  kernels  and  leaves  a  disgusting  dark  furrow,  unfitting 
the  corn  for  use.  It  feeds  upon  the  fruit  of  the  tomato  also.  The  naked, 
greenish-brown  caterpillar  is  marked  longitudinally  with  darker  stripes  when 
grown  and  is  about  \\  inches  long.  It  pupates  in  the  ground  through  the 
winter.  The  moth  has  dull  yellowish  fore  wings  tinged  with  green. 
The  hind  wings  are  paler.  Since  it  works  under  cover  of  the  hu.sk,  spray- 
ing is  of  no  use.  Fall  plowing  practised  by  all  neighbors  having  infested 
corn  will  materially  lessen  the  number  of  worms.  As  the  moths  fly  well,  it 
would  do  comi)aratively  little  good  for  one  to  plow  unless  the  near  neigh- 
bors unite  in  the  effort.     Rotation  of  crops  is  helpful, 


168 


BRANCH  ARTHROPODA 


The  tussock  moths  {Lymantri'idce)  (Fig.  138)  are  of  medium  size,  the 
antennge  of  the  males  being  more  broadly  i)ectiiiated  than  those  of  the 
females.  Ocelli  are  lacking.  In  some  species  the  females  are  wingless. 
The  legs  are  woolly  or  hairy.  The  larvse  are  more  beautiful  than  the  adults. 
They  have  several  bright  colored  tufts  of  hair  on  the  back  and  long  pencils 


Fig.  138. — Orgijin  Icncostig'ma:  a,  Larva;  h,  female  pupa;  c,  male  pujKi; 
d,  e,  male  moth;  /,  female  moth;  g,  same  ovipositing;  /;,  egg-mass;  i,  male 
cocoons;  k,  female  cocoons  with  moths  carrying  eggs.  All  slightly  en- 
larged.    (Howard,  Farmers'  Bull.,  U.  S.  Dept.  of  Agriculture,  1899.) 


of  hair  on  each  end  of  the  body.  The  sixth  and  seventh  segment  each 
bears  on  the  back  a  coral-red  scent  gland.  It  is  easy  to  guess  whether  these 
caterpillars  are  a  favorite  food  of  birds.  They  infest  our  shade  and  orchard 
trees.  The  eggs  are  usually  deposited  upon  the  cocoon  from  which  the  adult 
female  has  just  emerged,  so  they  may  be  destroyed  by  collecting  and  burn- 
ing the  cocoons  in  winter. 


LP]PIDOPTERA 


1G9 


>* 

^ 


A  B 

Fig.  139. — A,  Male,  and  B,  female,  gypsy  moths.    Natural  size.    (Forbush 
and  Fernald.) 


TH£tGOS    .- 
V/AJ  E  MON  T  HS 

VITAL  PERIOD^. 
The  GYrSY/LiFi 


R-jHc  WOS 

intheLI  FEoi 
K\QTH 


A 

lo: 


:x/ 


^-•J_0  DAYS_ 

Fig.  140. — The  life  cycle  of  the  gypsy  moth.  (Figures  after  Forbush 
and  Fernald.)  (Bull.  No.  121,  New  Hampshire  State  Experiment  Sta- 
tion, December,  190.5.) 


The  gypsy  moth  {Ocne'ria  di'spar)  (Fig.  139),  imported  from  Europe  in 
1868,  has  become  a  great  pest  of  forest  and  shade  trees  in  Massachusetts. 


170 


BRANCH    ARTHROPODA 


The  state  fought  it  in  every  possible  way,  employinji  hundreds  of  men  in 
spraying,  trunk-banding,  and  egg-collecting.  From  ISOOto  I'.IOO  Massa- 
chusetts spent  more  than  a  million  dollars  in  keeping  this  niotli  in  check. 
The  hawk  moths  {Sphin'gidce),  sphynx  moths  (Fig.  141),  or  humming- 
bird moths  have  a  stout,  spindle-shaped  body  and  long,  narrow,  exceed- 
ingly strong  wings.  The  sucking  tube  is  very  long,  sometimes  twice  as 
long  as  the  body.  When  not  in  use,  it  is  coiled  up  beneath  the  head  like  a 
watch-spring.  Their  rich  varied  tints  of  olive,  tan,  black,  or  yellow,  always 
subdued,  save  for  an  occasional  dash  of  bright  color  on  the  under  parts, 
mark  them  as  rarely  beautiful  creatures.     As  a  rule,  these  moths  love  the 


-^' 


Fig. 


141. — Tomato-worm    or     tobacco-worm:    larva,    pupa,    and    adult. 
(After  Walsh  and  Riley,  Am.  Ent.) 


twilight,  and  strangely  resemble  the  humming-birds  from  their  habit  of  rap- 
idly vibrating  their  wings  whi'le  poising  themselves  over  a  flower  and  suck- 
ing its  nectar. 

The  larva,  naked  and  cylindric,  usually  has  a  "  horn  "  on  the  back  of  the 
eighth  abdominal  segment.  These  caterpillars  are  usually  green  with 
several  oblique  light-colored  or  whitish  lines  on  each  side  (see  Fig.  141). 
When  resting  these  caterpillars  "  rear  the  front  of  the  body  up  in  the  air, 
curl  the  head  down  in  a  most  majestic  manner,  and  remain  thus  rigidly 
motionless  for  hours. "^  They  are  thus  supposed  to  resemble  the  Egyptian 
sphynx,  hence  the  name,  sphynx  moth.     They  feed  upon  the  leaves  of 

1  Kellogg,  331, 


LEPIDOPTERA 


171 


various  trees  or  plants,  the  tomato-worm  being  perhaps  the  most  familiar 
example.  When  full  ^rown  this  is  sometimes  3  inches  long.  The  pupa, 
which  lies  buried  in  the  ground,  has  a  firm,  naked,  dark  brown  wall,  and  is 
distinguished  by  the  peculiar  "  jug-handle  "  sheath,  in  which  the  sucking 
tube  is  developed.  Hand  picking  of  the  larvse,  fall  plowing,  and  rotation 
of  crops  are  the  best  remedies. 


Fig.  142. — Metamorphosis  of  monarch  butterfly  {Anosia  pkxippus): 
a,  Egg;  b,  larva;  c,  pupa;  d,  imago  or  adult.  (From  Jordan  and  Kellogg, 
"  Animal  Life,"  D.  Appleton  and  Co.,  Publishers.) 


The  monarch  or  milkweed  butterfly  (Ann'sia  plexip'pus)  (Fig.  142) 
is  one  of  our  most  abundant  sp(>cics.  Hundreds  or  even  thousands  of 
these  butterflies  may  sometimes  bo  seen  in  a  swarm,  or  ''  roosting  "  together 
in  trees.  Their  wings  are  reddish  brown,  bordered  with  black,  and  the 
veins  are  edged  with  black.  There  are  two  rows  of  white  spots  on  the  outer 
margins. 


172  BRANCH    ARTHROPOD A 

The  larva  when  grown  is  a  very  light  green  or  greenish  yellow,  and 
regularly  marked  with  shiny  black  and  yellow  bands.  On  the  second 
thoracic  and  the  eighth  abdominal  segment  there  is  a  pair  of  slender,  fleshy, 
black  filaments.  This  caterpillar  feeds  upon  the  leaves  of  the  milkweed. 
It  attains  its  growth  in  two  or  three  weeks,  when  it  pupates  from  nine  to 
fifteen  days  in  a  smooth,  bright  green  chrysalis  (Fig.  142),  which  is 
about  an  inch  long  and  beautifully  adorned  with  a  few  black  and  gilt  spots 
and  bands.     In  the  South  there  are  two  generations,  but  with  us  but  one. 

The  butterfly  is  protected  from  its  enemies,  the  birds,  by  an  ill-tasting 
acrid  fluid,  of  which  its  conspicuous  color  gives  warning.  The  power  of 
flight  is  strong  and  these  butterflies  migrate  in  winter.  The  monarch 
is  found  all  over  North  and  South  America  and  in  most  of  the  Pacific 
islands,  and  in  Australia  and  Western  Europe. 

It  is  closely  mimicked  by  the  viceroy  (see  Fig.  92,  p.  119),  a  smaller 
butterfly  which  is  not  distasteful,  but  is  protected  from  the  birds  by  its 
resemblance  to  the  odious  monarch.  The  viceroy  may  be  easily  dis- 
tinguished by  the  transverse  band  of  black  on  each  of  the  hind  wings. 
Its  larvae  feed  upon  the  willow,  poplar,  and  cottonwood.  The  larva  hiber- 
nates in  a  silk-lined  nest  made  of  a  rolled  leaf. 

The  swallow-tailed  butterflies  (Papilion'idoe)  are  a  large  and  interesting 
family,  having  a  sort  of  half-fluttering,  half-soaring  flight.  They  are 
easily  distinguished  by  their  large  size  and  their  black  and  yellow— or 
greenish-white — tiger-like  markings.  Twenty-one  species  are  found  in  the 
United  States.  The  wings  are  very  thickly  covered  with  scales.  They 
are  narrow  and  the  posterior  wings  end  in  a  club-shaped  prolongation  which 
is  supposed  to  call  the  attention  of  the  bird  to  the  less  vital  part.  The 
larvae  when  disturbed  project  a  pair  of  bright  colored  fleshy  "horns"  from  a 
slit  in  the  dorsal  wall  of  the  prothorax.  The  horns  exhale  an  odor  which  in 
some  species  is  exceedingly  disargeeable.^ 

The  zebra  swallow-tail  (Iphicll'des  a'jax)  differs  from  all  other  butterflies 
of  the  eastern  United  States  by  the  black  and  greenish-white  bands  on  its 
wings  and  by  its  exceedingly  long  "  tails."  This  butterfly  is  extremely 
interesting  to  the  scientist,  in  that  it  furnishes  an  example  of  dimorphism  or 
even  of  polymorphism.  All  the  broods  which  hatch  out  the  same  summer, 
and  there  may  be  several,  are  of  the  same  form  (ajax),  but  many  individuals 
pass  the  winter  in  the  chrysalis  stage,  some  (marcellus)  emerging  earlj^  in 
the  spring,  and  some  (telamonides)  appearing  in  late  spring.  The  marcellus 
form  has  "  tails  "  only  about  f  inch  long  tipped  with  white,  while  the 
telamonides  is  a  little  larger,  with  tails  nearly  an  inch  in  length  and 
bordered  on  each  side  of  their  distal  half  with  white;  while  ajax,  the  typ- 
ical form,  is  still  larger  and  has  longer  "  tails." 

The  time  of  emerging  seems  to  be  the  only  influence  controlling  this 
variation,  since  the  offspring  of  each  form,  when  maturing  the  same  season, 
produces  ajax,  when  maturing  early  the  following  spring,  produces  marcel- 
lus, and  late  the  following  spring,  telamonides. 

The  larva  of  this  species  is  light  green,  "  thickest  in  the  thorax,"  and  with 
transverse  markings  of  black  dots  and  lines  and  slender  yellow  stripes,  be- 
sides a  yellow-edged,  broad,  black,  velvety  stripe  on  the  thorax.  It  feeds 
upon  the  papaw. 

The  tiger  swallow-tail  {Papil'io  tur'nus),  another  common  species,  is  also 
dimorphic.  In  this  instance  the  dimorphism  is  sexual;  at  least  one  of  the 
forms,  glaucus,  is  represented  only  by  the  female. 

1  Comstock,  r,.  376. 


LEPIDOPTERA 


173 


The  cabbage  butterflies  {Pl'eris)  (Fig.  143),  of  which  there  are  three 
species  in  the  ditfcrcnt  sections  of  the  United  States,  are  the  most  de- 
structive to  ufiricultural  products  of  any  of  our  butterflies.  They  have 
three  broods  in  the  North  and  more  in  the  South. 

The  wings  of  Pieris  rupee  are  a  dirty  white  above,  tinged  with  yellowish 
in  the  female.  The  base  and  apex  of  the  fore  wings  are  blackish  and  the 
female  has  two  black  dots  on  the  fore  wings;  the  male  has  but  one.  There 
is  a  black  spot  on  the  anterior  margin  of  the  hind  wing.  In  the  male  it 
is  indistinct.  The  larva  is  green,  with  a  narrow  greenish-yellow  band  upon 
the  back  and  a  similar  narrow  broken  "  stigmatal  band."  It  is  covered 
with  fine  short  hairs.  It  feeds  upon  cabbage  and  other  cruciferous  plants. 
It  is  exceedingly  hard  to  combat,  from  the  facts  that  there  are  so  many 


Fig.  14.3. — Cabbage-worm  and  butterfly  {Pontia  ra'pce):  a,  Female; 
b,  egg;  c,  worm  eating  on  a  cabbage  leaf;  d,  suspended  chrysalis;  a,  c,  and 
d  slightly  enlarged.     (Chittenden,  Cir.  60,  B.  Ent.,  U.  S.  D.  A.) 


broods  and  that  the  larva  bores  into  the  heart  of  the  cabbage.  The  work 
of  extermination  must  necessarily  be  done  before  the  cabbage  begins  to 
head.  Fresh  pjTethrum  and  kerosene  emulsion  are  helpful.  It  is  hardly 
safe  to  use  Paris  green  except  with  quite  young  plants. 

The  gossamer  winged  butterflies  (Li/cop.ni'ihr)  include  three  well-marked 
groups  which  are  commonly  distinguished  by  their  various  colors  as  the 
"  blues,"  "  the  coppers,"  and  the  "  hair-streaks."  They  are  quite  small 
and  delicate.  The  larvae  are  slug-like.  The  "  blues "  are  often  seen 
flitting  about  mud-puddles.  Several  species  of  the  family  are  carnivorous. 
One  of  them,  the  "  harvester  "  (Fenis'eca  (arquin'ivs),  common  east  of  the 
Mississippi  River,  is  small,  with  the  "upper  surface  of  wings  dark  brovm, 
with  a  large  irregular  yellow  patch  on  the  disk  of  the  fore  wing  and  one  of 


174 


BRANCH    ARTHROPODA 


the  same  color  next  the  anal  angle  of  the  hind  wing."  It  is  a  friend  to  the 
fruit  grower,  for  its  larva  feeds  upon  woolly  plant-lice  like  the  apple-tree 
aphis  and  the  alder  blight. 

ORDER   XII.      HYMENOP'TERA 

This  order  is  represented  by  such  famiUar  insects  as  the 
bumble-bees,  yellow-jackets,  honey-bees,  ants,  wasps,  ichneu- 
mon flies,  saw-flies,  and  gall-flies. 

The  mouth  parts  (Fig.  144)  are  adapted  for  biting  or  sucking, 
the  mandibles  are  short  and  fitted  for  biting,  while  the  other 


Three  ocelli  or  simple  eyes 

°    /J^l^      Compound  eyes 
—Antennae 
Clypeus  (c). 


Mandibles 

Maxillary  palpi 

Maxilla 

Labial  palpi 


brum 
Palpifer  or  palpus  bearer 


Paraglossse  or  lateral  lobes 
of  the  tongue 


Lingula  or  tongue  attached  at 
the  base  of  the  labium 


Fig.  144. — Front  view  of  the  head  of  a  bee.     (Tenney.) 

mouth  parts,  as  the  maxillce,  labium,  the  maxillary  and  labial 
palpi,  are  more  or  less  modified  into  a  proboscis  for  taking  up 
liquid  food. 

The  wings  are  membranous  and  four  in  number.  The 
anterior  pair  is  larger  than  the  posterior.  The  student  will 
observe  that  the  body  and  wings  of  Hymenoptera  are  shorter 
than  those  of  the  dragon-fly  order  (Odonata). 

The  metamorphosis  is  complete.     The  larvae  are  maggot-like. 

Habits. — They  vary  much  in  habits.  Some  are  herbivorous 
(saw-flies),  some  form  galls,  others   are  parasitic  (ichneumon 


HYMENOPTERA 


175 


flies).  The  stinging  Hymenoptera,  on  account  of  their  efficient 
means  of  defense,  are  often  mimicked  (Fig.  132,  p.  160) — the 
bumble-bees  by  the  hawk-moths,  the  hornets  by  two  clear- 
winged  moths  of  the  genus  Sesia,  the  bee  by  the  drone-fly 
(Eristalis),  the  wasp  by  a  common  English  beetle  {Clytus 
eridus),  and  the  hornet  by  a  Nicaraguan  Hemiptera. 


Saw-flies  and  "Horntails." — Among  the  boring  Hymenoptera  are  the 
saw-flies,  horntails,  and  gall-flies. 

The  saw-flies  have  a  wide  head  and  thorax,  with  a  broad  joining  of  the 
base  of  the  abdomen  and  thorax.  The  ovipositor  consists  of  a  pair  of  saws 
with  which  slits  are  made  in  leaves  or  stems  where  the  eggs  are  laid.  The 
larvae  look  much  like  caterpillars,  but  may  be  distinguished  by  having  from 
twelve  to  sixteen  pro-legs  instead  of  ten.  Most  of  these  larvae  have  "  a 
curious  habit  of  curliiiy;  thi'  hind  end  of  the  body  sidewise  "  about  a  branch. 
The  rose-slug  and  currant -worm  are  familiar  examples. 

The  currant-worm  is  thr  larva  of 
the  saw-fly  (  Xrm'nlus  rihr'sih.  It  is 
a  "  criminal  fiuiiirant  "  and  has  left 
a  large  army  of  descendants.  The 
female  deposits  her  glossy  white  eggs 
along  the  ribs  of  the  first  leaves  of 
currant  and  gooseberry  bushes.  In 
ten  days  the  little  whitish  larvae 
hatch.  They  are  voracious  feeders 
and  will  strip  a  bush  of  every  leaf  if 
allowed  to  mature.  When  mature 
they  are  green  with  a  black  head  and 
black  spots  and  resemble  caterpillars. 
They  pupate  in  brownish  paper-like 
cocoons,  either  attached  to  the  bush 
or  hidden  in  the  ground.  There  are 
two  broods  in  a  season,  provided  the 
first  is  not  exterminated  by  a  liberal 
spraying  with  Paris  green  or  hellebore. 
If  the  spraying  is  thoroughly  done 
when  the  worms  are  quite  small,  they  are  easily  poisoned,  since,  like  all 
insects  with  biting  mouth  parts,  they  swallow  the  poison  with  their  food. 
If  any  of  the  larvae  escape,  the  spraying  must  be  repeated  for  the  second 
Isrood,  or  the  bushes  may  be  killed  outright  in  one  season.  If  the  spraying 
is  done  soon  after  the  first  brood  hatches  there  is  no  danger  of  poisoning  the 
fruit. 

The  horntails  (Siric'idce)  are  so  named  because  the  posterior  end  of  the 
abdomen  bears  a  spine  or  "  horn."  They  differ  from  the  saw-flies  in  hav- 
ing an  ovipositor  "  which  is  composed  of  five  long,  slender  pieces,"  adapted 
for  boring  instead  of  for  sawing.     There  are  several  species  in  America. 

The  pigeon  horntail  {TrS'mex  colUm'ha)  (Fig.  145)  has  a  cylindric  body 
about  }  inch  in  diameter.  It  is  U  inches  long,  with  rusty  red  thorax  and 
black  abdomen,  with  yellow  bands  and  spots  on  the  sides,"  a  yellow  "  horn- 
tail,"  and  smoky  transparent  wings.  The  female  pierces  holes  about  h  inch 
deep  in  elm,  oak,  sycamore,  or  maple  trees,  bending  the  ovipositor  at  right 


145. — Boring  saw-fly  or  horn- 
tail  {Tri'mex  colum'ba). 


176  BRANCH    ARTHROPOD A 

angles  to  the  body  in  boring,  and  deposits  her  eggs,  one  in  each  hole. 
When  the  larvae  hatch  they  do  much  injury  by  burrowing  into  the  heart- 
wood,  where  they  feed,  grow,  and  finally  form  cocoons  of  silk  and  fine  bits 
of  wood.  The  winged  adult  gnaws  its  way  out  through  the  bark.  The 
ichneumon  fly  ThaUasa  is  parasitic  upon  fremex. 

The  gall-flies  {Cynip'idoe)  live  in  closed  galls  during  the  larval  state,  and 
the  full-grown  larva  either  makes  a  hole  and  emerges  and  pupates  in  the 
ground,  or  it  pupates  in  the  gall  and  the  adult  makes  a  hole  through  which 
it  emerges.  The  adult  female  pierces  a  hole  in  the  tissue  of  the  leaf  with 
her  sharp-pointed  ovipositor  which  is  composed  of  "  several  needle-like 
or  awl-like  pieces."  In  the  incision  thus  made  she  deposits  one  or  more 
eggs.  When  the  larva  hatches  an  abnormal  growth  of  tissue  begins  to 
form  about  it,  caused,  perhaps,  from  some  irritating  excretions,  or  from 
the  physical  irritation  caused  by  the  pressure  of  the  irritating  body.  The 
tiny,  footless,  white,  maggot-like  larva  feeds,  probably  through  the  skin, 
on  the  sap  of  the  growing  gall.  When  the  gall  dies,  which  is  usually  about 
the  time  the  larva  is  grown,  it  dries  and  hardens  and  forms  a  protecting  case 
in  which  the  larva  (or  larvae)  pupates,  and  from  which  it  emerges  as  a  tiny 
gall-fly  in  the  first  or  second  spring  following. 

But  one  of  the  strange  things  about  these  gall-flies  is  that,  in  some  cases, 
the  successive  generations  of  the  same  species  are  not  of  the  same  form. 
The  adult  flies  of  one  generation,  which  consists  exclusively  of  females,  lay 
their  eggs  upon  a  certain  host-plant,  but  the  resulting  individuals  are  not 
at  all  Hke  their  mothers.  This  generation  includes  individuals  of  both 
sexes  which  have  developed  from  "  unfertilized  eggs,"  or  parthenogenetic- 
ally.  The  females  of  this  generation  lay  their  eggs  upon  a  different  host- 
plant,  develop  very  differently  shaped  galls  from  those  in  which  they 
grew  up,  but,  like  those  of  their  grandparents,  and  the  resulting  individuals 
are  like  their  own  grandparents.  Not  all  gall-flies  show  this  alternation  of 
generation,  some  species  appear  always  in  the  same  form,  but,  strange  to 
say,  they  are  usually  represented  only  by  females.  Although  there  are 
two  hundred  species  of  gall-flies,  each  species  infests  a  special  part,  leaf, 
branch,  or  root  of  one  or  more  particular  species  of  plants.  The  gall  pro- 
duced by  each  species  of  insect  is  of  a  definite  form.  This  is  a  remarkable 
manifestation  of  instinct.  "  It  is  impossible  that  intelligence  or  memory 
can  be  of  any  use  in  guiding  the  Cynipidce;  no  Cynips  ever  sees  its  young, 
none  ever  pricks  buds  a  second  season,  or  lives  to  know  the  results  that  fol- 
low the  act.  Natural  selection  alone  has  preserved  an  impulse  which  is 
released  by  seasonally  recurring  feelings,  sights,  or  smells  and  by  the  simul- 
taneous ripening  of  the  eggs  within  the  fly.  These  set  the  whole  physiologic 
apparatus  in  motion  and  secure  the  insertion  of  eggs  at  the  right  time  and  in 
the  right  place. "^ 

The  Guest  Gall-flies  {In'quilines). — There  are  many  gall-flies  which  do 
not  themselves  form  galls,  but  which  lay  their  eggs  in  the  galls  formed  by 
others.  The  larva?  feed  and  develop  here,  but  do  not  materially  disturb 
the  rightful  owners. 

Parasitic  hymenoptera  (Ichneumon'idoe)  are  of  great  economic  interest 
(Fig.  146).  Most  of  them  live  within  the  bodies  of  their  victims  during  the 
larval  stage,  the  egg  being  laid  either  within  or  upon  the  body  of  the  host. 
In  the  latter  case  the  larva  bores  its  way  into  the  body  and  feeds  upon  the 
blood,  so  that  the  host  is  not  killed  until  the  larva  is  grown.    Each  species 

1  Stratton. 


HYMENOPTERA 


177 


of  ichneumon  flies  has  its  special  host,  the  majority  of  them  being  cater- 
pillars.    The  largest  insect  of  this  family  belongs  to  genus  Thalessa. 

Thales'sa  luna'tor  has  a  body  2h  inches  long  and  the  insect  measures 
nearly  10  inches  from  the  tips  of  the  antenna'  to  the  end  of  the  ovipositor, 
and  is  parasitic  upon  the  larva  of  Trcimx  columha.  The  ichneumon  fly 
bores  a  hole  with  its  flc\il)]c  ovipositor,  which  is  6  inches  long,  into  the  tree 
infested  by  Tnim s,  mnl  d  posits  its  eggs  in  the  burrow  of  the  Trcmex  larva. 
When  the  ichneumoii  lar\a  luitches,  it  creeps  along  the  burrow  until  it 
reaches  its  victim,  the  horntail  larva, 
to  which  it  attaches  itself  and  feeds 
upon  its  juices.  Sometimes  the  female 
ichneumon  fly  gets  her  ovipositor  fast 
in  the  wood  and  it  holds  her  a  prisoner 
until  death. 

Other  important,  though  usually 
small,  parasitic  Hymenoptera  are  the 
braconids,  the  en.sign-flies,  and  the 
chalcid-flies.  While  the  larvae  of  para- 
sitic Hymenoptera  are  degenerate  in  the 
Bame  way  as  the  footless,  eyeless,  an- 
tennaeless  maggots  of  house-flics,  they 
are  not  more  so.  Their  parasitic  habit 
has  led  to  no  such  extraordinary  struc- 
tural specialization  through  degenera- 
tive loss,  or  reduction  of  parts  as  is  the 
usual  condition  in  other  i)anisites.  The 
adult  is  active  and  well  ileveloped. 

The  Stinging  Hymenoptera. — The  fe- 
males and  sterile  workers,  where  there 
are  such,  have  the  ovipositor  developed 
into  an  organ  of  defense,  the  sting. 
Females  may  be  distinguished  from  the 
males  by  having  six  segments  in  the  abdomen  instead  of  seven.  The 
group  includes  ants,  wasps,  and  bees. 

Ants  live  in  all  lands  and  in  very  various  conditions  and  occupations. 
All  of  the  2500  or  more  species  live  in  communities,  and  division  of  labor 
among  kinds  of  individuals  and,  consequently,  differentiation  of  structure, 
are  highly  developed.  Ants  are  easily  recognized  by  the  form  of  the  body, 
but  they  are  distinguished  from  other  insects  by  the  character  of  the  first 
one  or  two  segments  of  the  abdomen.  These  are  expanded  dorsally  into  a 
"  lens-shaped  scale  or  knot,"  which  varies  in  form  and  serves  as  a  peduncle 
to  the  rest  of  the  abdomen. 

The  ants'  nests  or  formicaries  are  composed  of  irregular  rooms  and  gal- 
leries which  may  be  mostly  underground,  or  have  a  large  portion  above 
ground,  as  a  mound  or  ant-hill,  or  may  bc^  tunnelled  out  in  the  wood  of  de- 
cayed trees.  "  In  the  tropics,"  says  Comstock,  "  a  greater  variety  of  these 
structures  occur  than  in  our  country.  .  .  .  One  colony  of  one  species 
has  been  known  to  have  two  hundred  mounds  covering  several  hundred 
square  yards.  Ants  are  also  very  good  road  makers,  sometimes  making 
clean  beaten  paths  or  working  out  covered  ways  under  rubbish." 

There  are  always  three  classes  of  ants  (Fig.  147)  in  a  community,  winged 
males  and  females,  and  wingless  workers,  sometimes  also  the  soldiers  and 
wingless,  but  fertile  males  and  females.    The  winged  males  and  females  at 
12 


of  ovipositing  on  cocoon  of  tent 
caterpillar.  Somewhat  enlarged. 
(After  Fiske.) 


178 


BRANCH    ARTHROPODA 


maturity  issue  simultaneously  from  the  nest  and  from  neighboring  nests, 
so  that  the  air  will  be  filled  with  thousands  of  ants  swarming  about  in  their 
mating  flight.  After  this  the  males  soon  die,  and  the  females  which  escape 
from  birds  and  other  animals  tear  off  their  wings  and  go  in  search  of  a  suit- 
able nesting  place.  Sometimes  the  queen 'Starts  the  new  colony  alone, 
while  in  other  species  the  workers  find  and  adopt  a  queen  and  form  a  new 
colony. 

Inside  the  nest  large  numbers  of  very  small  eggs  are  laid  in  "  little  piles 
heaped  together  in  various  rooms  and  sometimes  moved  about  by  the 
workers."'  The  larva?  are  small,  white,  footless,  helpless  grubs,  which  are 
fed  by  .the  workers  with  regurgitated  food  or  with  chewed  insects,  or  with 
dry  seeds  .nnd  vegetable  matter  from  the  granary  where  they  have  been 
stored.  Most  species  spin  cocoons  in  which  to  pupate — the  white  oval 
bodies  seen  carried  away  by  the  ants  when  the  nest  is  disturbed.    The  adults 


Fig.  147. — The  pavement  ant  (Tetramorium  ccespitum):  a,  Winged 
female;  b,  same  without  wings;  c,  male;  d,  worker;  e,  larva  of  female;  /, 
head  of  same;  g,  pupa  of  same;  all  enlarged.  (Marlatt,  Bull. U.S.  Dept. 
of  Agriculture.) 

are  unable  to  escape  from  these  cocoons  unaided  by  the  workers.  The 
workers  are  undeveloped  females  or  females  which  seldom  lay  eggs,  and  if 
they  do,  these  eggs  always  develop  into  males.  These  workers  not  only 
feed  the  colony,  but  do  all  the  work,  building  the  nests  and  defending  them 
against  enemies,  even  by  war  if  necessary. 

There  may  be  from  one  to  thirty  queens,  though  in  small  colonies  there  is 
usually  but  one.  As  these  queens  grow  old,  the  workers  seek  young  queens 
at  the  swarming  period  and  bring  them  into  the  nest.  Ants,  except  the 
males,  which  are  short  lived,  are  known  to  live  longer  than  most  social 
insects.  Lubbock  says  he  was  able  to  recognize  worker  ants  at  least  seven 
years  old,  and  one  queen  died  when  over  thirteen  years  old  and  another  lived 
more  than  fourteen  years.- 

1  Comstock. 

2  Lubbock,  "  Senses,  Instincts,  and  Intelligence  of  Ants,"  p.  233. 


HYMENOPTERA  179 

Although  ants  are  general  feeders  upon  animal  substances  and  fruit 
juices,  they  are  very  fond  of  sweet  substances  like  the  "  honey-dew  " 
given  off  by  aphids  when  stroked  by  the  ants'  antennae.  In  return  for 
this  choice  food  the  ants  shelter  the  aphid  eggs  in  their  nests  through  the 
winter  and  carry  the  young  plant-lice  to  tender  plants  in  the  spring.  When 
for  any  cause  these  plants  become  unsafe  or  unfit  for  the  food  of  the  aphids, 
the  ants  will  carry  them  to  other  plants.  If  ants  are  seen  running  up  and 
down  the  stem  of  some  favorite  plant,  one  may  know,  unless  there  is  a 
sweet  substance  exuding  from  bark  or  flower,  that  they  are  "  pasturing  their 
cows  "  upon  the  juices  of  tender  shoots  ami  newly  forming  buds.  A  little 
close  looking  will  reveal  myriads  of  tiny  i)lant-li('e  on  the  under  side  or  in 
the  axles  of  the  leaves.  Spraying  with  a  little  dilute  commercial  nicotin 
will  rid  the  plants  of  both  ants  and  plant-lice.  Arsenic  poisons  cannot 
affect  aphids  or  other  insects  having  sucking  mouth  parts,  since  their  food 
consists  of  the  internal  juices  of  plants  which  cannot  be  reached  by  the 
poison. 

There  are  many  other  insects  nihich  live  in  the  nests  of  ants.  In  1900 
Wasmann  recorded  1177  insects  living  in  the  nests  of  ants  (myrmecoph- 
ilous  insects),  many  of  which  were  beetles.  Most  of  these  insects  live 
a  commensal  life  with  the  ants.  It  is  not  known  of  what  advantage  they 
are  to  their  hosts.  The  guests,  however,  obtain  shelter,  food,  moderate 
temperature,  defense  against  enemies,  and  even,  in  the  case  of  migratory 
ants,  transportation.  In  the  case  of  some  small  beetles,  however,  there  is 
true  symbiosis  with  the  ants,  the  beetles  secreting  a  sweet  substance  which 
the  ants  eat  greedily,  and  in  return  the  ants  "clean,  care  for,  and  feed  by 
regurgitation"  the  degenerate  little  beetles. 

The  ants  furnish  an  example  of  a  perfect  communistic  society.  There  is 
no  special  rare  or  favoritism  for  wife  or  child  or  friend,  but  a  common  love 
for  the  whole  community.  "Everything  is  done  for  the  good  of  the  whole 
and  nothing  for  the  individual.  The  state  makes  wars,  provides  food  for 
all,  cares  for  the  children,  owns  all  the  property,  the  fate  of  each  one  is 
determined  by  the  accident  of  birth,  and  each  takes  up  its  work  without  a 
murmur.  .  .  .  This  perfect  commune  has  developed  courage,  patriotism, 
loyalty,  and  never-failing  industry,  but  also  war,  pillage,  slavery,  and  an 
utter  disregard  of  the  rights  of  other  communities  and  individuals. "^ 

Most  of  the  ants  which  have  been  described  in  this  coimtry  can  be  placed 
in  one  of  three  families:  (1)  Formic'idae,  in  which  is  foimd  the  interesting 
carpenter  ant  {Campon'otus  pennsylva'nicus),  one  of  the  largest  of  our  com- 
mon black  ants.  It  builds  its  nest  in  the  dead  interior  wood  of  living  trees 
and  wooden  buildings.  Here  also  is  the  mound-building  ant  {For'mica  ex- 
sectoi'des),  with  its  rust-red  head  and  thorax  and  black  abdomen  and  legs. 
Its  ant-hills  are  from  5  to  10  feet  in  diameter.  One  of  the  most  interest- 
ing of  the  family  is  the  slave-making  ant  (For'm ica  diffic'ilis) .  In  this  species 
the  workers  work  with  the  slaves,  but  Poli/cr'gus  rufes'cens,  a  European 
species,  depends  upon  the  slaves  to  do  all  the  work  for  the  community. 
The  adults  are  not  taken  captive,  but  in  war  and  pillaging  the  larvae  and 
pupae  are  some  of  them  eaten  and  some  of  them  carried  home,  where,  if  not 
eaten,  they  develop  into  the  adult  workers,  and  instinctively  go  to  work  for 
their  hosts,  building  nests,  bringing  food,  and  nursing  the  young.  In  some 
species  this  is  carried  on  to  such  an  extent  that  the  hosts  become  unfitted  for 
any  work  hut  that  of  warfare,  and  are  de])endent  solely  ujion  the  slaves  for 
shelter,  food,  and  all  the  necessary  work  of  the  community.     Thus  their 

'  Comstock,  p.  634.     . 


180  BRANCH    ARTHROPODA 

slave  making  has  reacted  upon  themselves,  rendering  them  unable  to  help 
themselves.  It  is  a  law  in  all  animal  life  that  dependence  upon  others 
renders  one  more  dependent,  while  dependence  upon  self  develops  inde- 
pendent powers. 

The  corn-louse  ant  {Las'ius  hrun'neus)  is  the  common  small  brown  ant  of 
our  pastures,  woods,  and  meadows.  It  is  of  especial  economic  interest  on 
account  of  the  care  it  bestows  on  the  corn-root  plant-louse.  The  eggs  of 
the  plant-louse  are  laid  in  the  ant's  nest,  where  they  are  sheltered  during  the 
winter.  In  the  spring  the  ants  place  the  young  aphids  upon  the  roots  of 
certain  knot-weeds  until  the  corn  has  germinated  and  then  remove  them  to 
the  corn-roots.  These  aphids  do  great  damage  in  the  Middle  West.  (See 
p.  144.) 

(2)  Poner'idae  is  the  smallest  family  in  number  of  species,  there  being  but 
about  twenty-five  known  in  this  country,  and  the  least  specialized,  that  is, 
the  least  differentiated  into  castes.  The  queen  and  workers  are  stingers. 
Their  nests  are  made  under  stones  or  logs. 

(3)  Mynnic'idae. — This  family  is  characterized  by  two  segments  in  the 
peduncle.  Usually  the  queen  and  workers  have  stings.  The  pupse  are 
naked.  To  this  family  belongs  the  tiny  "  red  ant  "  (Monomo'rium  pharao'- 
nis),  which  is  in  reality  a  light  yellow,  that  is  the  torment  of  housewives. 

The  agricultural  ants  {Pogonomyrmex)  live  in  the  southern  and  western 
states.  They,  with  the  exception  of  one  species,  live  in  nests  partly  under 
ground,  covered  with  conspicuous  mounds  in  open  sunny  places.  They  cut 
away  the  grass  immediately  about  the  nest.  It  has  been  popularly  believed 
that  they  sow  the  seed  for  their  food,  but  Wheeler  says  that  they  carry  out 
the  debris,  which  consists  of  chaff  and  sprouting  grain,  and  deposit  it  at  the 
edge  of  the  cleared  circle.  The  seeds  often  grow  and  do  yield  a  harvest  for 
their  next  winter's  stores,  though  not  intentionally  planted. 

Intelligence. — There  is  a  great  diversity  of  opinion  among 
scientists  who  have  experimented  with  ants  as  to  the  "  mental- 
ity "  of  these  insects.  Bethe^  and  others  hold  to  a  purely  me- 
chanical or  reflex  theory,  while  Loeb,  Wheeler,  and  others  at- 
tribute to  them  reflexes,  instincts,  and  animal  memory,  and 
Lubbock  and  Forel  give  them  a  considerable  degree  of  intelli- 
gence. Comstock  says  they  "  think. "^  Whether  they  are 
governed  by  one  or  all  of  these  attributes,  it  is  surely  probably 
that  the  mechanical  and  chemical  forces  which  affect  the 
nervous  activities  of  the  ants  may  also  influence  those  of  men, 
and  that  if  the  same  rigid  experiments  and  final  analyses  were 
applied  to  the  various  phases  of  man's  activities,  there  would 
result  quite  as  many  surprises  as  have  accompanied  the  experi- 
menting upon  insects,  indicating  that  many  of  his  activities 
are  responses  to  mechanical  stimuli,  and  yet  no  one  doubts 
that  man  possesses  intelligence.     Whether  the  activities  of  ants 

1  Kellogg,  544.  2  Comstock,  637. 


HYMENOPTERA  181 

are  governed  by  reflex  action,  instincts,  or  intelligence  (in  a 
limited  decree,  of  course),  or,  what  is  more  probable,  by  a  cer- 
tain combination  of  these,  they  certainly  perform  many  won- 
derful feats,  considering  the  fact  that  they  have  but  a  single 
set  of  tools,  the  mandibles.  They  use  these  to  dig  and  tunnel, 
to  obtain  food,  and  to  carry  and  manipulate  their  food,  to  fight, 
to  carry  tenderly  their  eggs  and  young,  or  to  cut  leaves  and  husks 
and  seeds.  Though  they  have  no  voice,  they  are  known  to 
communicate  by  means  of  touch  through  the  agency  of  the 
antennse.  It  is  believed  that  they  recognize  friend  or  foe  by 
the  odor. 

The  digger  wasps  (Sphcci'na)  are  a  group  of  closely  allied  families  of 
Hymenoptera.  They  may  be  distinguished  from  true  wasps  by  the  fact 
that  their  wings  lie  flat  above  the  body,  and  from  bees  by  the  adaptation  of 
their  legs  for  digging  and  walking.  They  are  all  solitary.  Each  female 
makes  her  own  nest  by  burrowing  in  the  ground  or  in  wood,  or  by  construct- 
ing a  tube  of  mud,  or  using  one  found  already  made.  In  this  nest  she  places 
certain  insects  which  she  has  paralyzed  but  not  killed,  by  stinging,  lays  an 
egg,  and  seals  up  the  cavity.  When  the  larva  hatches  it  feeds  upon  the  food 
thus  provided  for  it  by  the  mother.  The  parasitic  forms  lay  the  eggs  upon 
the  paralyzed  bodies  of  their  hosts,  and  the  guest-species  lay  them  in  the 
nests  of  other  wasps  or  bees,  where  the  larvae  feed  upon  the  food  prepared  by 
the  host  for  its  young. 

Familiar  examples  of  the  digger  wasps  are  the  mud  daubers  (Pelopce'us) 
of  our  attics  and  eaves.  It  is  thought  that  these  wasps  find  their  nests  again, 
after  going  in  search  of  insects  with  which  to  "provision"  their  nests,  by  the 
memory  and  recognition  of  localities,  for  they  go  from  place  to  place,  back 
and  forth  in  many  curious  zigzag  or  circular  routes,  but  find  their  way  back 
to  their  nests  readily. 

The  "tarantula-killer"  {Pcp'sis  formo'sa),  of  the  West  and  Southwest,  is 
a  large  solitary  wasp  which  provisions  its  nest  with  the  choicest  of  food,  such 
as  tarantulas,  though  many  a  hard  battle  is  necessary  to  procure  them. 
Sometimes  the  tarantula  makes  a  meal  of  the  wasp  instead  of  becoming  food 
for  its  young. 

The  true  wasps  (Vespi'na)  are  characterized  by  the  folding  of  their  wings 
lengthwise  like  a  fan  when  at  rest,  by  the  kidney-shaped  eyes,  and  by  the 
absence  of  bristles  or  spines  from  the  legs. 

One  family  (Eumcn'idoe)  of  the  true  wasps  leads  a  solitary  life.  One  of 
these  {Mono'bia  quad'ridens)  tunnels  into  wood  and  partitions  off  the 
tunnel,  making  a  cell  for  each  larva. 

Another  species  (Eu'hk  tx  s  frah  r'nus)  is  a  thorough  mason,  making  little 
jug-  or  vase-shaped  nests  of  r\ny  or  mud  which  it  attaches  to  the  stem  of  a 
plant.     It  provisions  it  with  cateriiillars,  often  with  canker-worms. 

The  social  wasps  (I'ex'pida:)  li^•e  in  communities  in  spring,  summer,  and 
autumn.  The  males  and  workers  die  in  the  autumn,  and  the  females 
(queens)  hibernate  through  the  winter  under  logs  or  stones  or  in  crevices. 
In  the  spring  each  queen  starts  a  colony.  She  makes  a  small  nest  containing 
a  few  brood-cells,  in  each  of  which  she  lays  an  egg.      The  hatching  larvae 


182 


BRANCH    AETHROPODA 


are  fed  by  the  queen  with  insects  captured,  killed,  and  somewhat  masticated 
by  herself.  In  a  few  days  the  larva?  pupate  in  the  cells  and  socjn  issue  as 
workers.  These  enlarge  the  nest,  adding  new  brood  cells,  which  the  queen 
fills  with  eggs;  which,  upon  hatching,  are  fed  by  the  work>'rs.  'Hius,  several 
broods  of  workers  arc  reared,  and  the  nest  is  continually  enlarged  to  make 
room  for  the  increasing  family.  Early  in  autumn  a  brood  is  hatched  con- 
taining males  and  females,  which  mate  probably  with  individuals  of  other 
communities,  and  at  the  approach  of  winter  most  of  the  colony  dies,  leaving 
only  a  few  hibernating  queens. 

The  nest  of  the  social  wasp  may  be  under  ground,  in  which  case  it  is  made 
of  partially  decayed  wood,  or  it  may  be  attached  to  bushes  or  trees  or  under 


Fig.  148. — A  hornet's  nest,  showing  two  horizontal  sections  of  comb,  one 
above  the  other,  and  the  many  layers  of  paper  surrounding  the  nest.  (Photo- 
graphed from  object.) 

th(>  eaves  of  buildings.  This  wood  is  formed  into  a  pulp  by  being  mast  icated 
with  saliva  and  chewed.  In  the  genus  PoUa'lcs  the  nests  consist  of  a  single 
cone  and  are  not  inclosed  in  an  envelop,  but  in  the  genus  I'r.s'/w;,  including 
the  yellow-jackets  and  hornets,  the  nest  (Fig.  14s i  consists  of  several  hori- 
zontal cones  suspended  one  above  the  other,  yet  m  pa  rated  by  a  considerable 
space  from  each  other,  and  the  whole  enveloped  in  a  waterproof  covering  of 
many  thicknesses  of  wasp-made  paper,  the  whole  nest  forming  a  globular 
or  cone-shaped  ball.  When  the  nest  is  to  be  enlarged  the  wasps  nibble  away 
the  inner  layers  of  the  enveloping  paste  and  add  new  layers  on  the  outside. 
Yellow-jackets  and  Hornets  (Vespa). — In  this  genus  the  body  of  the 
wasp  is  rather  stout  and  short  and  the  peduncle  is  very  short.     The  color 


HYMENOPTIORA  183 

is  black,  spotted,  and  banded  with  yellow,  from  which  we  are  all  glad  to 
take  "  warning,"  for  the  sting  of  a  hornet  is  painful  and  the  nest  contains 
thousands  of  individuals.  The  queens  are  larger  than  the  workers.  It 
may  be  interesting  to  know  that  the  males  have  no  sting.  They  may 
be  further  distinguished  from  the  other  forms  by  having  seven  segments 
in  the  abdomen  instead  of  six. 

The  social  wasps  do  not  store  up  food,  but  continually  feed  the  young 
throughout  the  larval  stage,  whicli  lasts  from  eight  to  fifteen  days,  with 
partially  masticated  insects.  Tlic  adults  "  fc*  d  ujwn  insects  or  decompos- 
ing animal  substancv^s  (fish  csix'cially  attracts  tluiii)  and  upon  exposed 
sweet  sub.stanc:'s,  such  as  syrups  and  pn's,T\i' I  Fruits." 

Bees  may  be  distingiuslied  from  all  oIIk  r  11\im(  tioptera  by  their  en- 
larged and  tiatt:ii;'(l  tarsal  segments,  wliicli,  except  in  the  I n'(/i/iJint >:.  are 
provided  witli  an  an-augemcut  for  carr^ip,!!;  ]>(il!>  ii.  It  is  said  tliat  the 
hairs  (at  least  on  the  head  and  thorax)  are  l)ranched  nr  i)luiii()se,  as  re\ealed 
by  the  microscope,  while  those  of  all  other  Hymeni>]!t(  la  arc  simple. 

The  nests  of  bees  are  always  provided  with  jxiUeii  or  lumey,  or  both. 
The  larvi3e  when  cjuite  young  are  fed  by  a  substance  called  "  bee-jelly," 
regurgitated  by  the  nurse  workers;  for  the  bee  colony,  like  those  of  other 
Hymenoptera,  consists  of  three  forms:  the  workers,  the  males  or  drones, 
and  the  female  (queen). 

The  short-tongued  bees  (Andrcn'ichr)  are  all  either  solitary  or  grega- 
rious, none  social.  Some  of  the  mining  bees,  genus  Andrena,  are  almost  as 
large  as  the  honey-bee  workers.  In  grassy  fields  they  sink  a  perpendicular 
shaft  into  the  ground  sometimes  to  the  depth  of  a  foot  or  more,  which 
branches  off  sidewise  to  the  cells.  Though  each  nest  is  solitary,  the  females 
often  build  close  together. 

The  smallest  of  our  bees  (Hulic'tus)  burrows  in  sand-banks  or  cliffs. 
Several  females  unite  to  "  make  a  burrow  into  the  bank,  after  which  each 
female  makes  passages  extending  sidewise  from  this  main  burrow  or 
public  corridor  to  her  own  cells.  While  .1  //<//■,  'mi  builds  \illages  composed 
of  individual  homes,  Halidus  makes  cities  com])f)se(l  of  ajiartment  houses."^ 

The  long-tongued  bees  (A'pidce)  have  the  lower  lip  highly  specialized 
for  obtainiuii  nectar  from  flowers.  The  basal  segment  of  the  labial  palpus 
is  also  elongated.  Some  of  this  family  are  solitary;  others,  guest-bees; 
a  few,  social. 

Among  the  solitary  long-tongued  bees  is  Megachi'le  acu'ta,  a  carpenter 
and  leaf-cutter,  which,  if  it  does  not  find  a  convenient  crevice  or  cavity 
rea<ly  made,  tunnels  out  a  tubular  cavity  in  wood  and  builds  a  thimble- 
shaped  nest  at  the  bottom  out  of  oblong  pieces  of  leaves  which  it  cuts  out 
for  itself,  and  fills  it  with  a  paste  of  pollen  and  nectar.  The  egg  is  then 
placed  upon  this  food  and  the  opening  tightly  plugged  up  with  circular 
pieces  of  leaves. 

The  little  blue  carpenter  bee  {Ccrat'ma  r/w/pZa)  builds  its  nest  in  dead  twigs 
of  sumach  or  in  the  liollows  of  other  i)laiifs.  The  female  fills  the  bottom  of 
the  nest  with  ]M)ll(>n,  lays  ati  egg  upon  it,  and  makes  a  partition  al)ov<"  the 
egg  out  of  pith  chips  made  in  forming  the  tunnel.  She  coiiliiiue^  making 
these  cells  until  the  tunnel  is  nearly  full,  then  she  rests  in  the  s|)ace  al)o\e  the 
last  cell  and  waits  until  the  yoimg  are  grown.  When  the  first  one  is 
ready  to  emerge,  it  tears  down  the  i)artition above  it  and  waits  till  each  one- 
has  performed  tiie  s.ime  process,  when  they  are  led  by  the  mother  into  the 
open  air.     Comstock  says  it   is  (he  only  instance  he  knows  of  a  solitary 

1  Comstock,  p.  666. 


184  BRANCH    ARTHROPODA 

bee  watching  her  nest.  The  old  nest  is  cleaned  out  by  the  whole  family 
and  used  again  by  one  of  them. 

The  guest-bees  (In'quilines)  infest  the  nests  of  both  solitary  and  social 
bees,  sonictiines  being  unwelcome  guests.  They  have,  of  course,  no 
worker  forms,  only  males  and  females,  since  work  is  not  necessary  when 
they  can  live  off  the  bounty  of  others.  Those  infesting  the  nests  of 
solitary  bees  steal  into  the  nest  before  it  is  completed  and  lay  their  eggs, 
which  hatch  before  those  of  the  host,  and  devour  the  food  intended  for  the 
young  of  the  rightful  owner.  Strangely  enough,  the  Inquilines  {Psith'yrus) 
seem  to  be  welcome,  for  if  they  were  not  the  bumble-bees  surely  would 
drive  them  out,  for  they  certainly  could.  The  female  lays  her  eggs  in  a 
bumble-bee's  nest,  and  when  the  larva;  hatch  they  are  cared  for  by  the  bum- 
ble-bees as  if  they  belonged  to  them.  Sometimes  the  guests  very  closely 
resemble  their  hosts  in  size  and  color,  but  in  other  cases  they  are  marked 
very  differently.  The  males  resemble  the  bumble-bees  so  closely  in  ap- 
pearance and  structure  that  it  is  difficult  to  determine  whether  they  belong 
to  Psithyrus  or  Bo^nbus,  but  the  females  are  easily  distinguished,  for  the 
pollen-basket  of  the  hind  legs  has  been  lost  through  disuse.  There  are 
no  workers  among  the  Psithyrus,  and  if  for  any  reason  the  supply  of  the 
host  should  fail  them,  the  guests  would  starve,  for  they  are  so  degenerate  as 
to  actually  be  unable  to  work.  Kellogg  says  these  guest-bees  "are  like 
bumble-bees  in  so  many  structural  details  unnecessary  for  deception  (mim- 
icry) that  they  must  be  looked  on  as  a  degenerate  offshoot  from  the  Bom'- 
bidae,"  that  is,  as  degenerate  bumble-bees. 

The  social  bees,  which  are  native,  belong  to  the  genus  Bombus.  The 
bumble-bees,  like  the  ants,  live  in  communities  having  three  kinds  of  in- 
dividuals: males,  females,  and  workers.  In  early  spring  each  queen  which 
has  survived  the  winter  by  hibernating  seeks  some  unoccupied  mole's  nest 
or  mouse's  nest  or  digs  a  cavity  in  the  ground  for  her  nest.  In  this  she 
deposits  a  ball-shaped  mixture  of  pollen  and  honey  and  lays  a  few  eggs, 
not  over  twenty,  upon  it.  Then  she  brings  another  supply  of  food  and  de- 
posits more  eggs.  When  the  first  larvae  hatch  they  feed  upon  the  food 
provided,  and  when  grown  each  spins  a  silken  cocoon  and  pupates.  These 
all  form  worker  bees,  which  enlarge  the  nest  and  provide  more  food .  The 
queen  lays  more  eggs  and  the  workers  now  enclose  the  larvae  in  waxen 
cells.  A  few  cells  also  are  filled  with  pollen  or  with  honey.  The  nest 
may  become  as  large  as  one's  head  and  is  covered  loosely-  with  bits  of  vege- 
tation. It  usually  has  two  or  more  openings.  "  Later  in  the  suniiner  males 
and  females  appear,  and  it  can  be  .said  to  the  credit  of  the  bumble-bee  (|uet;ns 
that  they  are  not  jealous,  but  allow  the  young  (jueens  to  live  with  them  in 
the  nest."  In  early  winter  all  liumble-bees  perish  e\<-ept  th(^  young  (jueens, 
which  hibernate  in  some  crack  or  crevice.  There  are  more  than  fifty  species 
of  buml)le-b(>es  (Homfms)  in  the  United  States.  They  differ  in  size  and  in 
the  arrangeni(>nt  of  the  black  and  yellow  color-patterns. 

The  honey  bee  is  a  native  of  Europe,  but  has  been  domesticated  the 
world  over.  "  It  has  been  known  and  cared  for  by  men  for  centuries. 
There  are  two  genera:  (1)  Melipona,  which  has  the  sting  blunted  and  ap- 
parently never  used  as  a  weapon,  lives  in  the  tropics  and  consists  of  numer- 
ous species  which  have  been  little  studied.  (2)  Apis  has  but  few  species, 
one  of  which  is  our  common  hive  bee. 

The  community  consists  normally  of  one  queen,  from  less  than  a  hundred 
to  several  hundred  males,  and  from  about  10, ()()()  workers  in  winter  to  .50,000 
in  summer.     The  queen  (Fig.  149,  K)  may  be  known  by  her  long  slender  ab- 


HYMENOPTER^ 


185 


domen  and  by  the  absence  of  wax  plates,  planta,  and  pollen  baskets.  The 
queen  is  hatched  from  a  fertilized  egg  in  a  large  cylindric,  vertical  cell 
(Fig.  149,  6-10),  and  fed  almost  wholly  upon  bee-jelly  regurgitated  by  the 
nurse  workers.  Here,  at  least,  is  one  strong  example  of  the  influence  of 
environment  during  development,  for  it  has  been  prove(l  that  there  is  no 
differen(!e  between  the  egg  from  which  the  queen  is  developed  and  the  one 
which  develop.s  into  the  worker. 

The  workers  (Fig.  149,  A),  which  are  the  bees  we  commonly  see,  are  smaller 
than  the  queens  and  males.     They  are  hatched  in  hexagonal,  horizontal 


Fig.  149. — Hive  bees  and  comb  (after  Schmeil).  .4,  Worker;  K,  queen; 
D,  drone;  1,  worker  with  cells  filled  with  honey  and  covered;  2,  cells  con- 
taining eggs,  larvae,  and  pupse;  3,  cells  containing  pollen;  4,  below  4  are 
regular  cells;  5,  drone  cells;  6-10,  queen  cells. 


cells,  and  fed,  like  the  males,  with  honey  and  bee-bread.  "  Workers  have 
wax  plates  under  the  abdominal  segments  and  pollen  baskets  on  the  outer 
surface  of  the  hind  tibiaj." 

The  males,  or  drones  (Fig.  149,  D),  have  a  hairy  thorax  and  a  heavy, 
broad,  blunt  body,  and,  like  the  queen,  lack  the  special  structures  of  the 
workers.  They  are  hatched  in  the  larger,  hexagonal,  horizontal  cells  from 
"  unfertilized  "  eggs.  After  the  swarming  season  is  over,  the  males  are 
driven  out  of  the  hive  or  stung  to  death  by  the  workers. 

When  a  community  becomes  too  large,  the  workers  prepare  a  "  queen- 
cell  "  and  develop  a  queen  by  process  of  special  feeding  and  care,  or,  it 


186  BRANCH    ARTHROPOD A 

may  be,  several  queens  are  so  developed.  When  these  young  queens  emerge, 
the  old  queens  at  once  enter  into  battle  with  them.  All  new  queens  are 
killed  but  one,  which  the  workers  guard.  The  old  queen  leaves  the  hive 
accompanied  by  a  swarm  of  workers  and  founds  a  new  colony.  The  work- 
ers at  once  begin  to  secrete  wax  by  gorging  themselves  with  honey  and  then 
together  "  hang  ciuietly  in  a  curtain-like  mass,  the  upper  bees  clinging  to 
the  roof  of  Ihc  hi\c  :uid  the  lower  ones  to  the  bees  above  them.  After 
about  twonty-four  hours  there  appear  little  flakes  of  wax  that  are  forced 
out  from  openings  between  the  ventral  abdominal  scgmcnls.  called  wax- 
pockets.  These  wax  scales  continue  to  increase  in  area  and  soon  i)ro- 
ject  beyond  the  margin,  and  either  tall  off  or  are  plucked  off  by  other  workers 
or  by  the  wax-producing  worker  itself."'  Other  workers  construct  it  into 
comb,  the  trowel-like  mandibles  pressing  it  into  hexagonal  cells.  Each 
comb  consists  of  a  double  layer  of  cells  separated  by  a  common  partition. 
New  wax  is  used  in  forming  cells  for  storing  honey,  but  old  wax  or  wax 
mixed  with  pollen  may  be  used  for  brood-cells.  The  workers  also  carry 
"  ■propolis,'"  a  sticky,  gummy  substance  with  which  they  at  once  stop  the 
chinks  of  their  hive.  They  carry  water  also  to  the  thirsty  larva;.  By 
steadily  and  rapidly  vibrating  their  wings  a  set  of  workers  stationed  at  the 
exit  or  scattered  about  the  floor  form  currents  of  air,  thus  ventilating  the 
hive.  Another  set  acts  as  scavengers  and  carry  off  all  dead  and  decaying 
debris  from  the  floor  and  walls.  Still  another  set  guards  the  entrance  from 
intruders,  such  as  neighboring  bees,  yellow-jackets,  and  l)ee-nioths.  For 
guarding  against  the  minute  bee-lice  and  bacterial  disease  s  the  help  of  man, 
"  the  bee-keeper,"  is  needed.  Kellogg  gives  an  obscr\ation  lii\-e  and  how- 
to  make  it,  whicli  would  be  w(>ll  worth  trying.  For  after  you  have  studied 
carefully  these,  shall  I  say,  intelligent  little  creatures  you  will  find  it,  indeed, 
difficult  to  decide  which  of  their  actions  are  reflex,  instinctive,  or  intelligent, 
or  which  are  all  of  these  combined. 

Classification. — 
Class  I.  Crusta'cea. 

Sub-class  En'tomos'traca. 

Order  I,  Phyllop'oda.  Brine  shrini}).    Dai^hnia. 

Order  II.  Ostrac'oda.  Cypris. 

Order        III.  Copep'oda.  Cyclops. 

Order         IV.  Cirripe'dia.  Barnacles. 

Sub-class  Mal'acos'traca. 

Order  I.  Phyllocar'dia.  Nebalia. 

Order  II.  Decap'oda.  Crayfish,  lobsters,  crabs. 

Order         III.  Arthros'traca.  (Jammarus.     Pill-bug. 

Class    II.  Arach'nida. 


Order 

I. 

Scorpion'ida. 

Scorpions. 

Order 

II. 

Phalangi'da. 

"Daddy-long-legs." 

Ordc^r 

III. 

Arane'ida. 

S])iders. 

Order 

IV 

.  Xiphosu'ra. 

Limulus     or     Horseshoe 
Crab. 

1  Kellogg,  p.  526, 

HYMENOPTERA                                                 187 

Class  III.  Myriap'oda. 

Order 

I.  Chilop'oda. 

Centipedes. 

Order 

II.  Diplop'oda. 

Millipeds. 

Class  IV.  . 

Insec'ta. 

Order 

I.  Ap'tera, or Thys- 

"Fish-moth"  and  "spring 

anu'ra. 

tails." 

Order 

II.  Ephemer'ida. 

May-flies. 

Order 

III.  Plectop'tera. 

Stone-flies. 

Order 

IV.  Odona'ta. 

Dragon-flies. 

Order 

V.  Isop'tera. 

Termites. 

Order 

VI.  Corroden'tia. 

"Book-lice." 

Order 

VII.  Malloph'aga. 

"Bird-lice." 

Order 

VIII.  Euplexop'tera. 

Earwigs. 

Order 

IX.  Orthop'tera. 

Grasshopper,  katy-did. 

Order 

X.  Physop'oda. 

Thrips. 

Order 

XI.  Hemip'tera. 

Chinch-hug,    plant    lice, 
and  cicada. 

Order 

XII.  Neurop'tera. 

Aphis-lion,  ant-lion. 

Order 

XIII.  Mecop'tera. 

Scorpion-flies. 

Order 

XIV.  Trichop'tera. 

Caddice  flies. 

Order 

XV.  Lepidop'tera. 

Butterflies,  moths. 

Order 

XVI.  Coleop'tera. 

Beetles. 

Order 

XVII.  Dip'tera. 

Flies. 

Order  XVIII.  Siphonap'tera. 

Fleas. 

Order 

XIX.  Hymenop'tera. 

Ants,  wasps,  bees. 

BRANCH   CHORDATA 

Branch  Chordata  comprises  many  of  our  best-known  and 
valued  animals. 


p]s)i'     ^Ami(pih 


Fig.  150. — A  series  of  embryos  at  three  comparable  and  progressive  stages 
of  development  (marked  I,  II,  III),  representing  each  of  the  classes  of 
vertebrated  animals  below  the  Mammalia.     (After  Hackel.) 


BRANCH    CHORDATA  189 

Characteristics. — They  all  have  (1)  Gill-slits  in  their  embry- 


r^  o  o  ^O 


^^^ 


^^4iy 


HL 


m 


m  nr 

Fig.  151. — A  series  of  embryos  at  three  comparable  and  progressive 
stages  of  development  (marked  I,  II,  III),  representing  four  different  di- 
visions of  the  class  MammaUa.     (After  Hackel.) 


onic  life  or  they  may  be  permanent;  (2)  a  notochord;  (3)  a  nerve 
chord  or  nervous  system  dorsal  to  the  notochord.     The  noto- 


190 


BRANCH  CHORDATA 


chord  is  a  smooth,  elastic  rod  typically  developed  from  the  endo- 
derm,  extending  along  the  median  line  between  the  alimentary 
tube  and  the  central  nervous  system.  It  is  encased  in  a  tough 
sheath  or  membrane  and  "forms  an  elastic  supporting  structure." 


Fig.  152. — Ideal  primitive  vertebrate,  seen  from  the  left  side:  na,  Nose; 
au,  eye;  md,  mouth;  g,  ear;  ks,  gill  openings;  x,  notochord;  mr,  spinal  tube; 
kg,  gill-vessels;  k,  gill-intestine;  hz,  heart;  ms,  muscles;  ??«a,  stomach; 
V,  intestinal  vein;  c,  body  cavity;  a,  aorta;  I,  liver;  d,  small  intestine;  e, 
ovary;  h,  testes;  ii,  kidney-canal;  af,  anus;  Ih,  true  or  leather  skin;  oh, 
outer  skin  (epidermis);  /,  skin-fold,  acting  as  a  fin.     (After  Hackel.) 

In  the  higher  forms  the  notochord  is  replaced  by  a  segmented 
cartilaginous  or  bony  vertebral  column. 

These  three  characteristics  may  not  be  easily  recognized  by 
the  beginner  as  he  looks  at  the  worm-like  BaVanoglos'sus,  the 


Fig.  153. 


-The  same  in  transverse  section  through  the  ovaries;  lettering  as 
in  the  preceding  figure.     (After  Hackel.) 


sac-like  sea-squirt,  or  the  small  fish-like  or  worm-like  A  m'phiox'us 
or  Lance'let,  but,  passing  by  these  low  forms  to  the  fishes,  frogs, 
reptiles,  birds,  and  mammals,  one  readily  finds  that  the  body  has 
two  cavities  instead  of  one,  as  in  the  invertebrates. 


ADELOCHORDA 


191 


Neural  Cavity. — The  upper  or  neural  cavity  contains  the  brain 
and  the  spinal  cord. 

Hemal  Cavity. — Below  the  vertebral  column  vv^ith  its  neural 
cavity  is  the  large  cavity  of  the  body,  the  hemal  cavity,  which 
contains  the  heart,  lungs,  digestive  organs,  and  other  viscera. 

Skeleton. — Most  of  these  higher  forms  have  an  internal  bony 
skeleton  or  a  cartilaginous  one,  as  in  some  fishes.  The  vertebral 
column,  or  backbone,  is  composed  of  a  varying  number  of  bones, 
each  called  a  vertebra,  hence  the  branch  is  named  Vertebrata, 
or,  if  named  from  the  notochord,  Chordata. 

Divisions  of  the  branch  are  usually 
made  to  distinguish  the  primitive  groups 
(Fig.  152)  or  Protovertebrates,  from  the 
true  Vertebrates. 

The  Protovertebrates  consist  of  three 
separate  groups  or  sub-phyla,  not  closely 
related  to  each  other,  but  each,  in  a 
primitive  way,  is  entitled  to  relationship 
with  the  Chordata  or  Vertebrata. 


SUB-PHYLUM  AND   CLASS  I. 
ADELOCHORDA 

The  Balanoglossus  is  the  principal 
genus  of  this  group,  though  two  deep- 
sea  forms  (Rhabdopleu'ra  and  Ceph'alo- 
dis'cus)  have  a  notochord,  and  the  latter 
has  a  pair  of  gill-slits,  but  in  other  ways 
they  are  like  the  polyzoans.  The  Bal- 
anoglossus (Fig.  154)  is  a  small  marine 
chordate.  Its  surface  is  ciliated.  It  is 
from  1  to  4  or  5  inches  in  length,  and,  by 
means  of  its  proboscis,  burrows  in  the 

mud  along  the  seashore.  A  study  of  the  animal  or  of  a  good 
figure  will  show  that  it  has  (1)  a  dorsal  nerve  cord,  (2)  a 
notochord,  and  (3)  gill-slits. 

Body  Regions. — The  Balanoglossus  is  divided  into  three 
body  regions:  the  proboscis,  a  club-shaped  hollow  anterior  por- 
tion opening  exteriorly  by  a  single  pore;  back  of  the  proboscis 


154, — Balano- 
p,  Proboscis; 
c,  "  collar  ";  gs,  gill- 
slits;  enlarged.  (From 
Dodge's  "  General  Zo- 
ology," American  Book 
Co.,  Publishers.) 


192  BRANCH    CHORDATA 

is  the  collar,  opening  by  two  spores  into  the  first  gill-slit;  the  re- 
mainder constitutes  the  flattened  but  nearly  cylindric  trunk. 
There  is  no  segmentation  of  the  body.  By  alternately  contract- 
ing and  dilating  the  proboscis  and  the  collar  the  Balanoglossus 
can  burrow  in  the  mud. 

Gill-slits. — On  the  dorsal  surface  of  the  anterior  portion  (the 
branchial  region)  of  the  trunk  is  a  double  row  of  gill-slits  which 
increase  in  number  throughout  life. 

Digestive  System. — The  mouth  is  situated  ventrally  at  the  base 
of  the  proboscis  just  within  the  collar,  and  from  it  the  alimentary 
canal  extends  to  the  posterior  extremity  of  the  body.  "Into  the 
dorsal  half  of  the  anterior  portion  of  the  alimentary  canal  open 
the  internal  gill  openings."  The  hepatic  cceca  bulge  out  in  ex- 
ternal prominences  in  the  middle  part  of  the  canal.  The 
anal  opening  is  at  the  posterior  end  of  the  body. 

The  notochord,  "a  blind  tube  surrounded  by  a  tough  mem- 
brane, extends  from  the  pharynx  into  the  proboscis."  There  are 
dorsal  and  ventral  nerve  strands  connected  by  nerves  in  the 
collar. 

A  dorsal  blood-vessel  lies  above  the  notochord. 

The  larvae  of  some  species  so  much  resembles  certain  echino- 
derms  that  the  Balanoglossus  was  formerly  placed  with  that 
branch. 

SUB-PHYLUM    AND    CLASS    II.     UROCHOR'DA    OR 
TUNICATA 

This  degenerate  group  is  represented  by  minute  animals  a  few 
centimeters  long  and  by  some  measuring  several  feet  in  length. 
They  are  found  singly  or  in  string-like  colonies  which  have  been 
developed  from  a  solitary  individual  by  budding,  the  two  forms 
thus  giving  rise  to  alternation  of  generations.  Multiplication 
is  both  sexual  and  asexual.  They  are  hermaphroditic,  but  cross- 
fertilization  occurs.  They  are  marine  and  most  of  them  are 
pelagic. 

The  most  common  forms,  the  "sea-squirts"  or  ascidians  (Fig. 
155),  are  surrounded  by  a  tough  elastic  bag,  one  end  of  which  is 
attached  to  stones.  At  the  other  end  is  a  large  round  oral 
aperture,  for  the  inlet  of  water  carrying  food  and  air,  and  near  it, 


UROCHORDA    OR   TUNICATA 


193 


on  one  side,  is  the  atrial  aperture,  for  the  exit  of  the  current. 
Sea-squirts  are  destitute  of  head  and  hmbs.  The  ventral  heart 
enclosed  in  a  pericardium  is  situated  between  the  gill  region  and 
the  stomach.  This  heart  has  the  peculiarity  of  changing  the 
direction  of  its  contractions.  When  the  blood  has  been  driven 
to  the  gills  for  a  while  it  rests  a  little,  and  then  forces  the  blood 
in  the  opposite  direction. 


Fig.  155.— Diagram  of  the  growth  of  a  sea-squirt  or  ascidian:  A,  a,  young 
free-swimming  stage;  a-,  intermediate  stage  just  before  becoming  fixed. 
B,  b,  Full-grown  sea-squirt,  rooted  to  the  sea  bottom  and  incapable  of 
movement:  m,  mouth;  e,  hollow  brain  with  eye;  g,  gill-slits;  h,  heart;  r,  rod 
of  gristle  in  free-swimming  form;  nv,  nerve  cord  in  same;  t,  tail  in  process 
of  absorption  in  intermediate  form.  (After  Haddon.)  (From  Baskett, 
"  The  Story  of  the  Fishes,"  D.  Appleton  and  Co.,  Publishers.) 


The  "sea-squirts"  were  formerly  called  "Tunicates,"  until  a 
study  of  their  larval  stage  showed  them  to  have  vertebrate  char- 
acteristics. The  larva  has  a  slender  finned  tail  containing  a 
notochord  and  a  nerve  cord.  They  furnish  an  example  of  retro- 
grade development.  They  are  free  for  a  few  hours,  then  be- 
come fixed  and  lose  the  notochord  and  nearly  all  traces  of  their 
vertebrate  characteristics  which  promised  a  higher  develop- 
ment. 


194 


BRANCH    CHORDATA 


SUB-PHYLUM  AND  CLASS  III.    ACRA'NIA  OR  AMPHIOXUS 

This  is  a  small  fish-like  chordate  2  or 
3  inches  in  length. 

Its  shape  is  one  found  for  the  first  time, 
that  of  narrow  ventral  and  dorsal  sur- 
faces and  deep  lateral  surfaces.  It  is 
pointed  at  both  ends.  It  falls  on  its  side 
when  not  in  motion. 

It  is  marine  and  lies  buried  in  the 
clean  sand  along  warm  seacoasts,  with 
its  ciliated  lips  protruding.  The  currents 
produced  by  the  cilia  bring  fresh  water 
with  its  oxygen  to  the  gills.  Small  organ- 
isms are  also  thus  furnished  for  food. 

The  Am'phiox'us  (Fig.  156)  has  no 
limbs,  no  skull,  no  well-differentiated 
brain,  and  no  heart,  but  it  has  a  noto- 
chord  (a  smooth  cylindric  rod  lying  above 
the  alimentary  tube),  a  nerve  cord  dorsal 
to  the  notochord,  numerous  gill-slits, 
and  an  alimentary  tube.  The  sexes  are 
separate. 

The  alimentary  tube  is  a  straight  tube 
consisting  of  mouth,  pharynx,  and  in- 
testine. On  the  right  side  of  the  pharynx 
is  a  blind  pouch,  the  so-called  liver. 

The  circulatory  system  consists  of  a  dor- 
sal arterial  trunk  and  a  ventral  venous 
trunk  connected  hj  lateral  arches.  The 
blood  is  colorless. 

Fig.  156. — Amphiox'us  lanceola'tus  :  a,  Anus; 
an,  eye;  b,  ventral  muscles;  c,  body  cavity;  ch, 
notochord;  d,  intestine;  do  and  du,  dorsal  and 
ventral  walls  of  intestine;  /,  fin-seam;  h,  skin; 
k,  gills;  ka,  gill-artery;  lb,  liver;  Iv,  liver-vein; 
wS  brain  vesicle;  m-,  spinal  marrow;  mg, 
stomach;  o,  mouth;  p,  ventral  pore;  r,  dorsal 
muscle;  s,  tail  fin;  t,  t,  aorta;  v,  intestinal  vein;  x,  boundary  between  gill 
intestine  and  stomach  intestine;  y,  hypobranchial  groove.    (After  Hackel.) 


Si-. 


CYCLOSTOMATA  195 

Locomotion. — The  Amphioxus  has  a  median  dorsal  fin  which 
extends  over  the  tail  both  dorsally  and  ventrally.  The  tail, 
that  portion  of  the  body  posterior  to  the  alimentary  tube  and 
filled  with  muscle,  is  the  chief  organ  of  locomotion.  It  is  noc- 
turnal, swimming  about  at  night,  but  quickly  returns  to  its 
burrow  if  disturbed.  It  can  burrow  in  the  sand  with  either  head 
or  tail. 

Nervous  System. — A  simple,  dorsal  nerve  lies  above  the  noto- 
chord.  It  does  not  reach  entirely  to  the  front  of  the  body.  Its 
anterior  tip  is  called  the  cerebral  vesicle,  in  which  there  is  an 
eye-spot.  There  is  also  possibly  an  olfactory  organ  consisting 
of  a  simple  pit  reaching  from  the  skin  down  into  the  anterior 
tip  of  the  nerve  cord. 


SUB-PHYLUM  IV.     CRANIA'TA  OR  VERTEBRA'TA 

These  are  chordates  having  a  brain  or  skull.  The  group 
includes  fishes,  amphil)ians,  reptiles,  birds,  and  mammals. 
The  body  is  usually  elongated  and  more  or  less  cylindric. 
The  mouth  is  situated  anteriorly.  Ventrally  and  near  it,  ex- 
cept in  Cyclostom'ata,  are  the  paired  nostrils.  Situated  in 
the  head  there  are  also  a  pair  of  eyes  and  a  pair  of  ears, 
though  the  ears  are  not  always  external.  Gill-slits  are 
never  more  than  seven  in  number,  and  partially  or  alto- 
gether disappear  in  the  adult  air-breathing  forms.  There 
are  one  or  two  pairs  of  jointed  limbs,  but  in  some  cases  they 
are  rudimentary  or  wanting. 


CLASS  I.     CY'CLOSTOM'ATA 

The  animals  of  this  class  inhabit  both  fresh  and  salt  water. 
They  have  no  lower  jaw.  The  mouth  is  suctorial,  the  skull 
cartilaginous,  the  notochord  persistent,  and  the  teeth  horny. 
The  neural  arches  are  rudimentary.  There  are  no  limbs  or 
scales  and  no  paired  fins;  but  unpaired  dorsal  and  caudal 
ones  are  present.  The  class  includes  the  lampreys  (Fig. 
157)    or    "lamprey-eels"    and    the    hag-fishes.     The    skin    is 


196  BRANCH    C'HOHDATA 

slimy  and  very  smooth.     The  gills  of  the  lampreys  open  into  a 
respiratory  tu})e  lying  below  the  gullet. 


F'ig.  157. — Lamprey  {Pdromy'zon  mari'nus).     (After  Goode.) 

They  are  parasitic  on  fishes  and  also  devour  crustaceans.  The 
slimy  eels  bore  into  fishes  and  eat  the  flesh. 

CLASS   II.     PIS'CES 

To  this  class  belong  the  true  fishes,  common  examples  of 
which  are  the  sunfish,  perch,  salmon,  catfish,  carp,  and  trout. 
They  are  aquatic,  gill-bearing,  poikilothermal,  usually  scaly, 
bilaterally  symmetric  finned  chordates. 

Shape. — The  typical  fish  is  wedge  shaped  (Fig.  158)  at  both 
ends,  so  that  it  can  pass  rapidly  through  the  water.  The  head 
is  large  and  pointed,  with  the  viscera  situated  near  it,  while  the 
trunk  is  long  and  tapering,  for  the  attachment  of  muscles  to  flex 
the  tail  in  locomotion.  Usually  the  body  is  more  or  less  flat- 
tened from  side  to  side,  though  it  may  be  quite  cylindric,  as  in 
the  eel,  or  flattened  dorsoventrally,  as  in  the  adult  flounder,  or 
the  body  may  be  long  and  slender,  as  in  the  pipe-fish  and  ril)bon- 
fish.  The  shape  conforms  largely  to  the  habits  and  habitat. 
The  fishes  having  the  under  side  flattened  usually  swim  near  or 
rest  upon  the  ])ottom  at  some  time,  as  our  catfish,  but  the  broad 
forms,  flattened  al:)Ove  and  below,  like  the  skates  and  flounders, 
live  upon  the  Ijottom  and  are  not  built  for  speed.  The  "flat 
fishes"  in  early  life  have  the  position  common  to  most  fishes,  Ijut 
in  adult  life  the  dorsoventral  plane  becomes  horizontal  instead 
of  vertical,  the  eye  lies  upon  the  upper  side,  and  the  color  of  the 
upper  side  becomes  dark  like  the  dorsal  side  of  most  fishes,  and 
the  under  side  light  like  the  ventral  side. 


PISCES 


197 


Size  and  Number. — Fishes  vary  in  length  from  an  inch  or  less 
to  30  or  40  feet.  Kellogg  says  there  are  about  "15,000  species 
of  fishes  known,  of  which  3000  species  live  in  North  America." 
Is  it  any  wonder  they  vary  in  size,  color,  and  habits?  They  are 
the  best  adapted  of  all  vertebrates  for  an  aquatic  life. 

Covering. — The  epidermis  consists  of  many  layers  of  proto- 
plasmic cells  with  a  very  thin  cuticle.  The  secretion  of  mucus 
by  the  great  numbers  of  "slime-cells"  of  the  epidermis  gives  to 
fishes  their  slippery  skin.  The  epidermis  contains  also  pigment 
cells.     The  dermis  consists  of  numerous  layers  of  connective 


Fig.  158. — Figure  of  a  whitefish,  showing  the  location  of  parts  usually- 
referred  to  in  descriptions:  1,  Dorsal  fin;  2,  adipose  fin;  3,  caudal  fin;  4, 
anal  fin;  5,  pectoral  fin;  6,  ventral  fin;  7,  lower  jaw,  or  mandible;  S,  upper 
jaw,  or  maxillary;  8a,  suppleinciilal  luaxillary;  9,  opercle;  10,  branchioste- 
gals;  11,  caudal  peduncle;  12,  lateral  line;  1.3,  series  of  crosswise  scales  usually 
counted;  14,  snout;  15,  eye;  16,  head;  17,  depth;  18,  base  of  caudal;  19,  dis- 
tance from  snout  to  nape  or  occiput.     (Report  U.  S.  F.  C,  1894.) 


tissue  and  furnishes  the  dermal  or  exoskeleton  or  scales  which  are 
usually  embedded  in  pockets  of  the  dermis. 

In  many  fishes  the  scales  overlap  each  other.  In  the  brown 
trout,  for  example,  the  greater  portion  of  each  scale  lies  under 
the  one  anterior  to  it,  and  the  remainder,  a  small  triangular  por- 
tion, is  covered  by  the  epidermis  only.  The  scales  sometimes 
receive  a  layer  of  enamel  or  vitrodentin  from  the  epidermis. 
(1)  The  placoid  scales  are  rhombic,  plate-like  bodies  often  bearing 
a  spine  covered  with  vitrodentin.  These  scales  are  placed  close 
together,  but  do  not  overlap.     (2)  The  ganoid  scales  also  are 


198  BRANCH    CHORDATA 

generally  "rhomboid  and  arranged  like  parquetry."  They  are 
covered  with  a  thick  coating  of  vitrodentin  which  gives  an 
iridescent  effect,  and  are  often  closely  articulated  into  a  coat  of 
armor.  (3)  The  cycloid  scales  are  closely  related.  They  are 
placed  loosely  in  the  pockets  and  arranged  in  rows.  In  over- 
lapping, one  scale  covers  parts  of  two  scales  posterior  to  it.  The 
middle  part  of  the  scale  is  surrounded  by  concentric  lines  from 
which  proceed  radiating  Hnes.  (4)  The  ctenoid  scales  (see  Fig. 
174)  have  the  posterior  edges  truncate  and  the  free  margin 
toothed.  The  scales  are  often  striated  or  polished,  and  this 
gives  rise  to  various  colors,  especially  the  iridescent  gleam  on 
the  sides  of  the  fish. 

Color. — The  color  in  general  harmonizes  with  its  environment. 
Most  of  the  fresh-water  fishes  are  dark  colored  (olive  or  greenish) 
above  and  whitish  below,  so  that  to  the  enemies  from  above, 
as  fish-eating  birds,  the  form  appears  indistinct  in  the  water,  and 
to  the  enemies  below  they  look  white  like  the  light.  Many  are 
variously  dotted  or  striped  with  lighter  or  darker  colors,  thus 
simulating  the  lights  and  shadows  among  the  weeds  and  grasses. 
The  scales  reflect  all  the  hues  and  tints  of  the  rainbow,  causing 
the  fishes  to  rival  the  birds  in  beauty.  The  males  of  some  species 
put  on  l)righter  colors  at  the  spawning  season.  Some  species 
have  the  power  of  changing  color  at  once  to  meet  the  surround- 
ings, as  the  pipe-fishes,  some  sticklebacks,  the  plaice,  and  the  little 
Oligocottus  snyderi,  of  Monterey  Bay,  California.  Many  others 
change  the  colors  more  gradually.  Recent  experiments  upon 
fishes  in  aquaria  have  shown  that  if  the  light  be  thrown  from 
below  and  cut  off  from  above,  the  upper  part  grows  light  colored 
and  the  lower  part  dark  colored.  This  would  seem  to  show  that 
the  colors  are  due  to  the  action  of  light,  but  while  many  fishes 
in  caves  are  colorless,  it  is  said  that  those  in  the  black  depths 
of  the  ocean  may  be  either  pearly  white  or  black;  so  the  question 
is  yet  unsolved.     Many  deep-sea  forms  are  phosphorescent. 

Some  fishes  have  special  protective  resemblance,  as  the  leaf- 
finned  sea-horse,  the  pipe-fish,  and  some  angler-fishes,  the  pos- 
terior fins  of  which  are  bedecked  with  fringes  "that  exactly 
mimic  seaweed."  The  mouse-fish,  or  Sargassum,  is  colored  to 
harmonize  with  the  gulf  weed,  Sargassum,  among  which  plants 
it  lives. 


PISCES  199 

"  The  color  of  fishes  is  of  threefold  origin.  The  silvery  luster  is  due  to 
crystals  of  guanin  which  occur  in  the  skin.  The  other  colors  are  due 
partly  to  numerous  strongly  jjigmented  fat-cells  and  partly  to  the  chro- 
matophores  in  the  derma,  whicli  under  the  control  of  the  nervous  system 
can  alter  their  forms  and  extent  and  thus  produce  color  changes  in  the 
fish,  thus  adapting  it  to  its  surroundings.  It  is  of  interest  to  note  that 
destruction  of  the  eyes  results  in  loss  of  power  to  change  color. "' 


Locomotion  and  Appendages. — The  appendages  of  fishes,  ex- 
cept in  rare  instances,  are  the  unpaired  dorsal,  anal,  and  caudal 
fins,  and  the  paired  pectoral  and  ventral  fins.  "Fishes  are 
the  only  vertebrates  having  median  fins  supported  by  fin-rays." 
The  fin-rays  supporting  all  the  fins  are  of  dermal  origin.  The 
locomotion  is  mainly  produced  by  the  flexing  of  the  body  and 
tail,  so  as  to  propel  the  usually  spindle-shaped  animal  through 
the  water.  The  fins  aid  in  directing  the  movements  of  the  fish, 
as  does  also  the  air-bladder,  which  regulates  the  specific  gravity 
of  the  fish. 

The  skeleton  is  cartilaginous  or  bony.  The  notochord  of  the 
protovertebrate  becomes  surrounded  by  a  mesodermic  sheath 
which  produces  the  centra  of  the  vertebrae,  consisting  of  cartilage 
or  bone.  From  the  centra  are  outgrowths  dorsally  which  give 
rise  to  the  neural  tul)e,  "an  inverted  tunnel  of  cartilage"  en- 
closing the  cerebrospinal  cavity,  and  ventral  (hemal)  outgrowths 
protecting  the  viscera.  The  vertel^rse  are  usually  amphicelous, 
and  the  notochord  persists  in  the  cavities  between  the  centra. 
The  neural  arches  extend  throughout  the  spinal  column,  while 
the  hemal  are  complete  only  in  the  tail.  In  the  trunk  the 
hemal  spines  are  absent  and  the  hemal  processes  are  divided 
into  basal  processes  and  ribs  which  surround  the  viscera.  There 
is  no  sternum. 

The  skull  (Fig.  159)  encloses  the  brain  which  does  not  fill  the 
cavity.  The  lower  jaw  is  movable  and  usually  bears  teeth. 
Some  fishes  have  many  teeth ;  others,  few  or  none.  They  have 
no  other  prehensile  organs. 

The  pectoral  and  ventral  fins  are  homologous  with  the  paired 
limbs  of  the  higher  vertebrates,  but  lack  many  of  the  bones  of  the 
higher  forms,  as  a  comparison  of  the  bones  of  man's  arm  with 
those  of  the  pectoral  fins  will  show. 

1  Hertwig's  "  Manual  of  Zoology,"  Kingsley,  p.  559. 


200  BRANCH    CHORDATA 

Digestive  System. — The  food  is  principally  animal.  Food 
securing  is,  of  course,  by  the  mouth.  The  mouths  of  fishes  vary 
in  size,  shape,  and  position,  according  to  the  food  and  feeding 
habits.  The  digestive  tract  is  large,  near  the  region  of  the  phar- 
ynx, but  narrows  into  a  tube  in  which  there  is  little  distinction 


Fig.  159. — Right  lateral  view  of  skull  of  M.  dolomieu,  with  other  bones; 
natural  size:  Pmx,  premaxillary ;  PL,  palatine;  na.,  nasal;  Eth.,  ethmoid; 
Prf.,  prefrontal;  As.,  alisphenoid ;  Fr.,  frontal;  Ptf.,  postfrontal;  Sq., 
squamosal;  Pa.,  parietal;  Pt.o.,  pterotic;  S.O.,  supra-occipital;  si.,  supra- 
linear;  Ep.o.,  epiotic;  k,  interneural  spines;  La.,  lacrymal;  Pr.s.,  para- 
sphenoid;  S.or.,  suborbital;  Pr.o.,  prootic;  Bs.,  basisphenoid ;  G.Hy., 
glossohyal;  D,.  dentary;  Art.,  articular;  Mx.,  maxillary;  a,  admaxillary; 
Enpt.,  entopterygoid;  EcpL,  ectopterygoid;  M.Pt.,  metapterygoid; 
Pst.T.,  posttemporal;  Pr..s.,  proscapula;  Pf.,  pectoral  fin;  Hyo.C,  hypo- 
coracoid;  Op.,  operculum;  S.Op.,  suboperculum ;  At^g.,  angular;  Sym., 
symplectic;  tc.s.,  neural  spine;  Ps/o.T.,  post (Tot cm pnral;  7",  telcotemporal; 
T',  lower  telcotemporal;  Bs.R.,  branchiostcgal  rays;  P.Op,  preopcrcu- 
lum;  I. Op.,  interoperculum ;  H.M.,  hyomandibular;  Qu.,  quadrate;  r.,  rib; 
Ast.,  actinosts;  Hyp.C,  hypercoracoid.     (Shufcldt.) 


between  the  parts.  Many  fishes  have  pyloric  ceca  at  the  junc- 
tion of  the  stomach  and  intestine.  Others  have  a  spiral  valve, 
a  fold  of  mucous  membrane  increasing  the  digestive  surface. 
There  is  a  large  liver  and  a  spleen  and  usually  a  pancreas  and 
gall-bladder. 


PISCES 


201 


Excretion,— The  nephridea  unite  in  a  i^air  of  large  kidneys. 
The  ureter  may  or  may  not  empty  into  a  urinary  l)ladder. 

Circulation  (Fig.  160). — The  heart  is  surrounded  by  a  peri- 
cardium. It  consists  of  simis  venosus,  auricle,  ventricle,  and 
conus  arteriosus.  The  blood,  which  is  red,  goes  from  the  gills 
over  the  body.     The  veins  collect  it  and  return  it  to  the  sinus 


Branchial  artery^ 

Arterial  bulb  ^, 

Ventricle  of  the  heart  .^. 

Auricle  of  the  heart  — 

Venous  sinus--- 

Vena  portse,  liver,  etc.". 


Branchial  vessels 


-Dorsal  artery 


Kidneys 


Dorsal  artery  or  aorta 


Fig.  160. — The  circulatory  apparatus  of  a  fish.     (Tenney.) 


venosus,  from  which  it  passes  through  the  parts  of  the  heart  in  the 
order  named,  and  the  circulation  begins  anew. 

Respiration  is  by  gills  except  in  the  lung  fishes,  which  take  the 
mechanically  dissolved  air  from  the  water  and  give  off  waste 
matter.  The  gills  arise  as  paired  pouches  of  the  pharynx  and 
open  on  the  exterior  by  gill-slits.  They  are  attached  to  the 
branchial  arches  and  are  persistent  through  life. 


202 


BRANCH  CHORDATA 


The  brain  is  of  the  vertebral  type,  but  small,  and  occupies  but 
a  small  portion  of  the  cranium.  The  cerebrum  is  comparatively 
small.  The  cerebellum  is  sometimes  large.  The  optic  and  ol- 
factory lobes  are  conspicuous  (Fig.  161).  The  medulla  is  also 
present,  all  the  parts  being  distinct  and  visible  from  above. 
The  brain  sends  off  at  least  ten  pairs  of 
nerves. 

The  Senses. — Of  all  the  sense  organs, 
the  most  noticeable  are  those  along  the 
lateral  line.  The  lateral  line  on  either 
side  of  the  fish  from  tail  to  head  is 
"marked  by  a  groove  in  the  scales  which 
opens  to  the  exterior  by  numerous  canals 
through  the  scales."  (Examine  several 
scales  along  the  lateral  line.)  The  func- 
tion of  the  lateral  line  is  possibly  to  as- 
certain the  water  pressure  at  different 
depths. 

The  skin  and  especially  the  lips  are 
the  seat  of  the  sense  of  touch. 

The  eye  has  several  peculiarities.     The 
lens  is  very  convex,  owing  to  the  slight  re- 
fraction from  the  light  in  passing  from  the 
water  into  the  cornea.     The  eye  is  short  sighted,  since  light  is 
so  absorbed  by  water  as  to  render  objects  a  short  distance  away 
invisible.     Lids  are  wanting  or  very  poorly  developed.     Only 


Fig.  161.— Brain  of 
cod :  og,  Olfactory 
lia;     ch,    cerebral 

hemispheres;  ol,  optic 

lobes;    c,    cerebellum; 

mo,  medulla  oblongata. 

(Tenney.) 


Fig.    lt)2  -   LiK  ifu'qa 
developed  eyes. 


A  blnid  hsli  containing  unborn  young  with  well- 
(iMgenniann,  Bulletin  .526,  U.  S.  F.  C,  1902.) 


a  few  fishes  have  a  nictitating  membrane.     There  are  no  tears. 
Through  disuse  for  generations  the  cave  fishes  have  lost  their 

sight  (Fig.  162). 


PISCES 


203 


The  ear'  has  a  relative  size  found  in  no  other  vertebrate. 
There  are  no  external  ears.  Many  teleosts  have  two  otoliths. 
Experiments  show  that  the  ear  is  principally  for  a  balancing 
organ. 


Fig.    163.— Stickleback  and  nest.     (From  Baskett,   "  The  Story  of  the 
Fishes,"    D.    Appleton   and   Co.,    Publishers.) 


1  "  The  maigre  is  said  to  produce  a  flute-like  note  audible  in  twenty 
fathoms.  Many  fishes  utter  sounds,  but  perhaps  the  grunt  (Hoemulon) 
on  the  outer  Florida  reef  is  most  remarkable  for  the  variation  of  the  sound. 
.  .  .  The  dog-fish  utters  a  croak  or  bark.  The  gizard-shad  (Hippo- 
campus), eels,  catfish,  porcupine-fish,  sunfish,  carp,  gurnards,  etc.,  utter 
sounds  either  accidental  or  intentional.  The  sound,  a  single  note,  fre- 
quently uttered  by  the  eel  is,  according  to  Abbott,  more  distinctly  mu- 
sical than  those  made  by  other  fishes."     (Holder.) 


204 


BRANCH  CHORDATA 


The  function  of  the  nostrils  is  smeUing  and  not  breathing. 
For  none  of  them,  except  those  in  the  hag-fish  and  lung  fish,  open 
into  the  mouth.  The  odors  must  come  through  the  water.  All 
fishes  proper  have  two  nostrils.  Experimental  proof  of  smell  is 
lacking,  but  the  well-developed  olfactory  lobes  and  nerves  argue 
that  the  sense  cannot  be  entirely  wanting. 

Emotions. — If  you  have  ever  tried  the  sport  of  fishing  with 
hook  and  line,  you  know  that  fishes  have  emotions  of  fear  and 
curiosity.  Romanes  says  they  have  also  those  of  play,  anger, 
pugnacity,  and  jealousy.  In  some  species  parental  affection  is 
proved  by  the  building  of  nests  (Fig.  163)  and  the  care  of  the 
young;  sexual  feelings,  by  courtship;  social  or  gregarious  in- 
stincts, by  their  "schools."^ 


Fig.  164.— Sawfish. 


Upper,  profile   view.      Lower, 

{Pristis  pedinatus.) 


view  of  under  part. 


Means  of  Defense. — Fishes  most  often  protect  themselves 
from  their  enemies  by  their  close  resemblance  to  the  surround- 
ings, or  by  their  swift  movements,  darting  away  at  the  least  in- 
timation of  danger.  But  many  are  also  armed  with  weapons 
of  defense,  such  as  the  spines  connected  with  the  fins  of  the  dog- 
fish and  the  catfish.  The  mucus  which  flows  over  the  spines 
is  somewhat  poisonous,  making  the  wound  painful.  The 
" Scorpanoids"  have  a  little  poison  sac  on  each  side  near  the  tip 
from  which  the  poison  flows  down  a  groove  of  the  spine  into  the 
wound.  The  Thallassophryne  has,  besides  the  dorsal  hollow 
poisonous  spines,  in  which  the  poison  sac  is  situated  at  the  base, 
non-poisonous  spines  on  the  gill-covers.  The  porcupine-fish 
{Di'odon  macula'ta)  and  the  globe-fish  {Chylomyc' terus  geome'tri- 
cus)  have  spines  all  over  the  body.  The  "surgeons"  and  rays 
^  Baskett. 


PISCES 


205 


have  spines  on  the  tail.  The  thresher-shark  (Alo'pias  vulpes) 
has  its  pHable  tail  prolonged  into  a  terrible  weapon,  with  which, 
it  is  said,  it  can  kill  a  whale.  This  lashing  tail  serves  a  second 
purpose  by  so  frightening  the  small  fishes  that  they  crowd  to- 
gether and  are  thus  easily  obtained  for  food.  The  "devil-fish" 
strikes  terrible  blows  with  its  broad  pectoral  fins.     The  saw-fish 


Fig.  165.— Sword-fish  (Tetraptu'rus),  y.  llou 
caught  with  rod  and  reel  at  Santa  Cutalina  isl 
vol.  xxviii,  1908.) 


-fin  tuna,  and   y<^llow  tail, 
md.     (Bulletin  "of  B.  of  F., 


(Fig.  164),  sword-fish  (Fig.  165),  and  the  like  use  their  long 
strong  jaws  as  frightful  weapons.  The  torpedo  and  other 
electrical  fishes  surprise  and  stun  their  victims  by  an  electric 
shock. 

Influence  of  Temperature. — Species  differ  in  their  ability  to 
endure  cold  or  heat.     The  brook  trout  loves  the  cool  water  of 


206  BRANCH    CHORDATA 

the  mountain  streams,  while  the  catfish  can  live  in  exceedingly 
warm  water.  "Fishes  have  been  found  in  hot  springs  of  120°  F." 
The  Protop'terus  of  Africa  and  Asia  "so  completely  slimes  a  ball 
of  mud  around  it  that  it  may  live  thus  for  more  than  one  season."^ 
Other  fishes  bury  themselves  in  the  mud  and  cestivate  through 
the  dry  season.  The  little  "mud-skippers"  move  from  pond  to 
pond  by  the  use  of  their  pectoral  fins.  Other  fishes  migrate  to 
cooler  waters  as  necessity  requires.  In  winter  some  of  the 
fishes  of  our  small  streams  hibernate  in  the  mud,  while  some, 
as  the  carp,  may  have  the  water  frozen  into  ice  about  them  and 
live  when  thawed  out. 

Development. — The  sexes  are  separate.  Multiplication  is 
by  eggs,  which  are  numerous.  The  cod  is  said  to  lay  one 
million  eggs.  In  the  bony  fishes  the  eggs  are  naked  and  numer- 
ous, and  fertilization  usually  takes  place  in  the  water. 

In  sharks  the  eggs  are  few  and  are  protected  by  a  horny  shell. 
In  most  sharks  and  in  a  few  bony  fishes  the  eggs  are  fertilized 
and  hatched  within  the  body  of  the  mother  fish.  Mating  takes 
place  in  a  few  viviparous  forms  only.  Most  fishes  do  not  care 
for  their  young  "fry,"  but  the  stickleback  builds  a  nest  and  de- 
fends it  with  great  courage.  There  is  usually  no  metamorphosis, 
but  some  ocean  species  change  almost  as  much  as  frogs. 

SUB-CLASS   I.      ELASMOBRAN'CHII 

The  rays  and  sharks  represent  the  Sela'chil,  in  which  are  found 
all  the  living  elasmobranchs.  They  have  no  operculum  (gill- 
cover)  and  no  air-bladder.  The  skeleton  is  cartilaginous.  The 
mouth  and  nostrils  are  ventral  and  the  tail  heterocercal.^ 
The  scales  are  small.  "The  cloaca  is  the  common  outlet  for  the 
rectum,  renal  and  reproductive  ducts."  Some  are  viviparous, 
others  lay  a  few  eggs,  each  enclosed  in  a  chitinous  case. 

Sharks  vary  in  length  from  2  to  60  feet,  the  majority  being 
under  8  feet  in  length.  Some  are  large  and  voracious,  a  few 
dangerous  even  to  man.  Hornaday  says  the  only  loss  of  life 
from  sharks  on  our  coast  occurred  in  1830.  They  feed  mostly 
upon  fishes. 

The  rays  (Rai'idoe)  have  the  body  disk  shaped,  broad,  and  flat, 

1  Baekett.  2  Glossary. 


HOLOCEPHALI 


207 


the  pectoral  fins  being  much  expanded.  The  skin  is  roughened 
by  spines  or  prickles.  Rays  most  generally  live  on  the  bottom  of 
the  sea,  feeding  upon  fishes, 
mollusks,  crabs,  and  other  bot- 
tom-frequenting animals. 

To  the  order  Sela'chii  belong 
the  skates  (Fig.  166),  sting-rays, 
and  torpedoes  or  electric-rays. 
The  saw-fish  ray  also  belongs 
to  this  order.  Its  formidable, 
sharp-toothed  snout,  several 
feet  in  length,  makes  it  a 
dreaded  enemy.  It  disables 
its  prey  by  dashing  into  a 
school  of  fishes,  striking  right 
and  left.  Then  it  eats  its  dis- 
abled prey  at  leisure. 


holoceph'ali 


SUB-CLASS  II 

This    group    is    represented 
on  our  Atlantic  coast  by  the 


Fig.  166. 


Common  skate  {Ra'ia 
erinacea.) 

Chimm'ra  monstro'sa  (Fig.  167). 

The  Holoceph' all  were  formerly  abundant,  but  are  now  repre- 
sented by  only  a  few  genera.  The  skeleton  is  cartilaginous  and 
the  skin  is  smooth.  These  are  very  peculiar  looking  fishes,  as  a 
glance  at  Fig.  167  will  show.     The  nostrils  and  mouth  are  ven- 


Fig.  167. — Chiiuoe'ra  monstro'sa.     (.Clan 


tral.  In  general  they  resemble  the  sharks  in  their  compressed 
form,  but  differ  from  them  by  the  large  head  and  small  mouth. 
"Fossil  remains  are  found  from  the  lower  Jurassic  rocks  upward." 


208 


BRANCH    CHORDATA 
SUB-CLASS  III.      DIP'nOI 


The  "lung  fishes"  are  snake-hke  or  eel-Hke  (Fig.  168),  and 
bear  small,  soft,  cycloid  scales,  small  paired  fins,  and  a  diphycer- 


Fig.  168. — Lung  fish  {Protop'lerus  annecferis).     (Boas.) 


Fig.  159. — The  Ccr'atoilus  of  (^ufciishunl,  :in  air-breathing  and  water- 
breathing  mudfish  of  the  ancient  type,  with  paddle  fins.  (P>om  Baskett, 
"  The  Story  of  the  Fishes,"  D.  Appleton  and  Co.,  Publishers.) 

cal  caudal  fin.     The  skeleton  is  largely  cartilage  and  the  noto- 
chord  persistent.   They  live  in  fresh  water,  and  usually  breathe 


TELEOSTOMI 


209 


by  gills,  but  when  the  water  gives  out  or  becomes  unfit  for  use 
the  swim-bladder,  which  may  be  single  or  double,  is  used  for 
lungs.  It  opens  into  the  ventral  side  of  the  gullet  and  contains 
air-cells.     In  this  case  the  air  enters  through  the  nose. 

They  are  interesting  as  showing  how  land  forms  may  have 
originated  from  aquatic  forms.  There  are  only  three  existing 
genera:  the  Lepidosi'ren,  of  the  Amazon;  the  Cer'atodus  (Fig. 
169),  of  Australia,  and  the  Protop'terus,  of  Africa.  The  Protop- 
terus  (see  Fig.  168)  "can  live  out  of  water,  it  burrows  in  the 
mud  at  the  dry  season  and  builds  a  cocoon  lined  with  mucus  in 
which  it  remains  quiescent  until  the  wet  season."^ 

SUB-CLASS   IV.      TELEOS'TOMI 

To  this  extensive  sub-class  belong  our  bony  fishes,  including 
most  of  the  living  fishes.     It  contains  thousands  of  species. 


Fig.  170. — Renioras  and  shark,  showing  dorsal  fins  modified  into  sucking 
disks,  by  which  the  remora  attaches  itself  to  the  shark  in  its  commensal  life, 
thus  securing  free  transportation.  (From  Baskett,  "  The  Story  of  the 
Fishes,"  D.  Appleton  and  Co.,  Publishers.) 


Familiar  examples  are  the  perch,  sunfish,  catfish,  trout,  carp, 

pike,  cod,  and  salmon.     The  mouth  is  terminal.     The  nostrils 

are  on  the  upper  surface  of  the  snout.     The  tail  is  homocercal 

1  Hertwig. 

14 


210  BRANCH    CHORDATA 

(see  Fig.  170,  Rem'ora),  the  scales  are  either  ctenoid  or  cycloid. 
These  fishes  vary  in  shape.  They  vary  in  size  from  our  little 
darter,  1|  inches  in  length,  to  the  "horse-mackerel,"  which  may 
weigh  as  much  as  a  cow.  They  differ  in  habits  from  the  pre- 
daceous,  swift  pikes  and  pickerels  to  the  peculiar  flounder  on 
the  bottom  of  the  sea. 

The  Remora  (Fig.  170)  is  a  lazy  fish.  It  has  a  sucker  on 
top  of  its  head,  by  which  it  holds  fast  to  sharks  or  larger  fishes, 
and  thus  saves  itself  the  effort  of  locomotion. 

Order  I.  Crossopteryg'ii. — There  are  only  two  existing  genera, 
Polyp'terus  and  Calamoichthys,  of  Africa. 

Order  II.  Chondros'tei  (Sturgeons)  (Fig.  171). — They  have 
paired  fins  with  no  basal  lobe,  supported  by  dermal  rays.  The 
pelvic  fins  are  abdominal.  The  vertebral  column  consists  of  the 
notochord  with  cartilaginous  arches.     The  tail  is  heterocercal. 


Fig.   171. — Common  sturgeon   {Acipen'ficr  slu'rio 
1899.) 


The  mouth  is  ventral,  projectile,  and  toothless,  and  sucks  up 
worms  and  larvae  from  the  muddy  bottom.  The  surface  is 
roughened  l)y  separate  scales  and  by  five  rows  of  bony  plates. 

Sturgeons  are  found  in  streams  and  lakes  of  the  Northern 
Hemisphere  and  are  the  largest  fresh-water  fishes.  Those  of  the 
lower  Columbia  River  sometimes  weigh  from  800  to  a  1000 
pounds. 

From  the  swim-bladder  of  the  sturgeon,  glue,  cement,  court- 
plaster,  and  isinglass  are  made.  The  egg-masses,  called  roe, 
furnish  caviare. 

Order  III.  Holos'tei. — Familiar  examples  of  this  order  are  the 
gar-pike  and  the  mud-fish,  often  called  dog-fish,  of  the  streams 
of  the  central  states. 

The  skull  is  ossified.  The  scales  are  ganoid  or  cycloid;  the 
tail,  diphycercal  or  homocercal.     The  pelvic  fins  are  abdominal. 


TELEOSTOMI 


211 


The  spiral  valve  is  present.     The  double  air-bladder  aids  in 
breathing. 

The  gar-pike  (Fig.  172)  has  a  cylindric  body  covered  by 
rhomboid,  bony  scales,  which  are  coated  with  enamel.  The 
snout  is  long  and  bony  and  armed  with  sharp  teeth.  This  fish 
is  voracious.  There  are  three  species  found  in  the  fresh  water  of 
North  and  Central  America,  including  Cuba.  They  are  from 
5  to  10  feet  in  length. 


Gar-pike  {Lcpidos'teus  oa'tieus).     (After  Tenney.) 


The  mud-fish  or  bow-fin  is  abundant  in  the  shallow  waters  of 
the  Mississippi  Valley.  It  has  a  somewhat  bony  skeleton  and  a 
soft  flesh,  which  is  not  generally  used  as  food. 

Both  the  gar-pike  and  the  bow-fin  come  to  the  surface  to  emit 
gases  and  to  take  in  a  fresh  supply  of  air.  They  can  live  some 
time  out  of  water,  when  they  use  the  air-liladder  as  a  sort  of 
lung. 


Fig.  173.— Cycloid  scale. 


Fig.  174. — Ctenoid  scale. 


The  three  foregoing  orders  are  often  spoken  of  as  Ganoids. 
Though  now  insignificant,  they  were  abundant  in  the  Paleozoic 
and  Mesozoic  Epochs. 

Order  IV.  Teleos'tei. — The  skeleton  is  well  ossified.  The  tail 
is  usually  homocercal.  There  is  no  spiral  valve  save  in  one 
genus.  The  scales  are  cycloid  or  ctenoid  (Figs.  173,  174),  or, 
in  rare  instances,  the  body  is  naked.     The  operculum  is  always 


212  BRANCH    CHORDATA 

present.  The  swim-bladder  is  usually  present,  but  its  duct  is 
often  closed.     Eyes  are  usually  conspicuous  and  without  lids. 

Reproduction  is  by  eggs.  They  are  small  and  numerous, 
and  are  fertilized  in  the  water  by  the  milt  deposited  by 
the  male  at  the  same  time.  This  accounts  for  the  enormous 
schools  of  some  fishes  in  certain  places  at  the  breeding  season 
each  year.  They  sometimes  go  thousands  of  miles  to  reach  these 
spawning  places.  The  salmon  come  from  the  salt  water  up 
into  the  rivers  to  deposit  their  eggs,  which  are  about  the  size 
of  peas,  in  depressions  or  nests.  When  very  small  the  young 
salmon  are  banded  and  called  parr,  and  later  become  silvery 
smolt.  The  perches  form  nests  or  hollows  in  the  ground  near 
the  shore.  In  a  form  allied  to  the  perch  both  male  and 
female  form  these  depressions  and  guard  the  eggs.  The  male 
Chromis  of  Lake  Tiberias  carries  the  eggs  and  young  in  its 
mouth.  The  stickleback  (see  Fig.  163),  a  small  fresh-water 
fish,  builds  a  nest  and  the  male  cares  for  the  young.  The 
male  Loph'ohranch  carries  the  eggs  in  a  ventral  pouch,  forcing 
the  young  out  by  pressing  the  pouch  against  a  stone.  An 
Indian  ocean  form  carries  the  eggs  in  a  pouch  formed  by  the 
ventral  fins  of  the  mother. 

Sub-order  Physos'tomi  includes  the  catfishes,  buffalo,  carp, 
salmon,  trout,  herring,  eels,  etc. 


The  catfishes  (Silu'ridce)  are  devoid  of  scales.  The  majority  live  in 
fresh  water.  The  head  is  flat  and  the  wide  mouth  is  provided  with  long 
thread-like  feelers  or  barbels.  They  have,  for  a  weapon  of  defense,  a  strong 
stiff  spine  for  the  first  ray  of  dorsal  and  pectoral  fins.  They  are  sluggish 
and  abound  in  the  muddy  streams  of  the  Mississippi  Valley.  The  flesh  is 
quite  free  from  bones  and  is  much  used  for  food.  Some  catfishes  weigh 
150  pounds. 

The  common  catfish  guards  its  young.  The  South  American  catfish 
carries  its  eggs  and  young  in  its  mouth.  Other  South  American  species 
build  nests  of  leaves  in  wliich  they  place  their  young.  An  electric  catfish 
inhabits  the  Nile,  and  blind  catfishes  live  in  subterranean  streams  of  Penn- 
sylvania. 

Carps,  bufifalo  fishes,  and  suckers  have  a  naked  head  and  usually  scaly 
body.  The  flesh  is  bony  and  not  of  much  food  value,  yet  quite  largely  used 
because  inexpensive  on  account  of  the  immense  number  seined.  They  have 
a  toothless  sucking  mouth  and  are  vegetable  feeders,  hence  the  intestine 
is  long.  The  air-bladder  consists  of  two  or  three  Hnks.  .  .  .  The 
shiners,  minnows,  and  dace  (Fig.  175)  belong  to  this  group.  The  black- 
nosed  dace  {Rhmich'thys  atronasus)  is  a  nest  builder.  Both  male  and 
female  form  a  depression  in  which  the  eggs  are  deposited.     Both  parents 


TELEOSTOMI 


213 


then  cover  them  by  a  heap  of  stones  placed  layer  upon  layer  to  a  height 
of  about  10  inches. 

The   salmon    (Salmoit'ld(i-)  are  found   in   Europe  and   North  America. 
They  live  in  salt  water,  but  often  go  thousands  of  miles  to  their  fresh-water 


Fig.  175. — Showing  longitudinal  section  of  the  nest  of  a  dace  with  the 
male  and  female  fish  in  the  nest.  The  stream  flows  in  the  direction  indi- 
cated by  the  arrow  at  the  upper  left-hand  corner  of  the  figure.  (Bull. 
Bureau  of  Fisheries,  190S.) 

breeding  places.  The  white  fish  and  the  various  species  of  fresh-water 
trout  belong  to  this  group  and  are  delicious  food  fishes.  The  red-spotted 
brook  trout  is  most  widely  known,  and  is  found  from  Maine  to  Dakota. 
On  account  of  its  great  cunning  the  trout  is  much  sought  by  sportsmen,  and 
is  fast  becoming  exterminated  in  its  natural  haunts. 


,«,^*^^ 


i'A  P  '^mm^^'^mKm'tmjmu.'i  imis  in  M'  '.i- , 


Fig.  176. — Eel  {Atiguil'la  chri/sypa).     (Bu! 


Eels  (Anguil'lidfe)  have  the  body  greatly  elongated,  having  many  ver- 
tebrae, and  being  almost  cylindric  (Fig.  176).  They  have  no  ventral  fins 
and  the  "  pharyngeal  and  oiMTcular  hones  are  more  or  less  deficient." 
The  scales  are  minute  or  entirely  wanting  and  the  skin  is  very  slimy.     They 


214 


BRANCH  CHORDATA 


are  mostly  tropical  and  marine.  The  true  eels,  genus  Anguilla,  which 
crawl  "  in  the  mud  and  ooze  of  brackish  and  fresh  waters  of  most  regions, 
are  absent  on  the  Pacific  Coast  of  America."'  They  are  very  voracious 
and  are  especially  fond  of  shrimp  and  crayfish,  which  they  find  by  over- 
turning stones.  They  will  also  devour  dead  fish.  They  sometimes  go 
considerable  distances  in  the  damp  vegetation  on  land,  thus  avoiding  water- 
falls and  other  obstructions.  The  females  are  larger  and  lighter  colored 
than  the  males  and  have  smaller  eyes  and  higher  fins.  In  the  spring  the 
eggs  are  deposited  in  the  sea.  It  is  said  the  young  ascend  rivers  and  after 
two  or  three  years  return  to  the  sea  to  spawn.  A  Brazilian  eel  {Gymno'tus) 
is  electric,  having  two  pairs  of  batteries  in  the  ventral  portion  of  its  long 
tail.  "  A  metamorphosis  is  known  only  in  the  eel-like  fishes,  the  larvae 
of  which  are  flat,  transparent  forms,  with  colorless  blood,  enormous  tails, 
and  very  small  trunks.  The  larva?  normally  occur  in  the  sea  at  a  depth 
of  several  hundred  fathoms.  "^ 


^\^''.,'^-  ^■^IMJ^<M^■^<^■^ 


Fig.  177. — Winter  flounder  (Pseu'do})lciiro>u'c'tes  america' nus) .     (After 
Goode.) 


The  blind  fishes  (Amblyop'sidoe)  of  Mammoth  Cave  are  colorless  and 
translucent.  They  have  rudimentary  eyes,  but  have  lost  their  sight 
through  disuse  for  many  generations.  They  have  no  lateral  line.  Their 
knowledge  of  danger  comes  through  the  hearing,  which  is  very  acute.  The 
head  is  very  flat  and  the  mouth  is  directed  upward,  as  food  is  scarce  near 
the  bottom.  They  come  to  the  surface  to  feed,  but  at  the  slightest  noise 
dart  beneath  stones  at  the  bottom. 

Sub-order  Anacan'thini  includes  the  cod,  haddock,  whiting,  as  well  as  the 
flat  fishes — soles,  turbots,  flounders,  halibuts,  etc.  There  are  nearly  a 
hundred  species  of  codfish.  Some  reach  a  length  of  4  or  5  feet  and  weigh 
100  pounds.  The  female  lays  nine  or  ten  millions  of  eggs  in  a  single  season. 
They  rise  to  the  surface  of  the  sea  and  hatch  in  about  twenty  days. 
There  is  one  fresh-water  codfish. 

The  haddock  resembles  the  cod  in  appearance  and  habits. 

'  Jordan.  "^ 

2  Kingsley's  translation  of  Hert  wig's  "  Zoology." 


TELEOSTOMI 


215 


Many  kinds  of  flounders  lie  upon  the  left  side  upon  the  sea  bottom. 
The  young  flounder  is  somewhat  cylindric,  has  an  eye  on  each  side,  and 
swims  vertically  like  other  fishes.  The  eye  moves  over  by  successive  stages 
until  both  eyes  are  upon  the  upper  or  right  side  (Fig.  177).  The  mouth 
also  becomes  crooked  and  the  under  side  of  the  fish  becomes  white.  The 
upper  side  is  colored  and  its  color  may  be  changed  to  suit  the  surroundings. 
"  The  blind  flounder  docs  not  adapt  its  color  to  its  surroundings." 

The  halibut  sometimes  attains  a  weight  of  400  pounds  and  a  length  of 
6  feet.     It  is  found  on  both  sides  of  the  Atlantic  Ocean. 

Sub-order  Acanthop'teri. — The  spiny-rayed  fishes  constitute 
a  large  group,  inclucUng  the  greater  number  of  the  marine  fishes 
and  many  fresh-water  species.  The  stickleback,  perch,  mullet, 
mackerel,  our  river  bass  and  sea  bass,  and  our  common  sunfish 
belong  here. 

The  perch  is  a  carnivorous  fish  found  both  in  fresh  water  and  along  the 
seacoast  and  is  widely  distributed.  These  fishes  spawn  in  winter,  forming 
nests  in  the  gravel  near  the  shore. 


-Large-mouthetl  black  bass  (Microp'terus  salmoidcs). 
U.  S.  F.  C,  1900.) 


The  bass  and  sunfish  are  common  in  our  streams.  The  black  bass  is 
found  in  clear  runninu;  water  from  the  St.  Lawrence  to  Dakota  and  south  to 
Arkansas  (Figs.  17S,  179).  Its  length  is  1  to  2  feet  and  it  weighs  from  2  to 
7  pounds.  It  varies  in  color,  the  adult  being  olive  green.  It  is  a  great 
game  fish.  The  sunfishes  have  short  compressed  bodies.  They  are 
carnivorous,  gamy,  and  usually  brightly  colored. 

The  green  sunfish  (Lepo'mis  cyanell'us),  common  in  streams  east  of  the 
Mississippi,  makes  a  nest  of  gravel  in  the  shallow  water  and  deposits  several 
thousand  eggs,  which  the  male  guards. 

The  seventy  species  of  mackerel  {Scom'hridw)  are  all  marine.  In  early 
summer  great  schools  appear  on  the  shores  from  Greenland  south  to  Cape 
Hatteras.     The  young  from  one  female  number  from  500,000  to  600,0C)0. 


216 


BRANCH  CHORDATA 


As  they  go  north  after  spawning  vast  numbers  are  caught,  whole  fleets 
being  engaged  in  catching  them.  The  mackerel  is  phosphorescent  and  the 
light  from  these  enormous  schools  is  so  great  that  they  can  be  seined  at 
night.  They  are  sold  either  fresh  or  salted.  One  of  the  largest  and  swift- 
est of  the  mackerel  tribe  is  the  sword-fish,  in  which  the  upper  jaw  is  de- 
veloped into  a  long,  bony,  sword-like  projection  (see  p.  205).  This  forms  a 
strong  weapon,  as  the  fish  dashes  into  schools  of  fishes,  cutting  and  slashing 
and  devouring  them.  It  has  been  known  to  pierce  the  wooden  and  copper 
bottoms  of  vessels.  It  does  not  breed  in  North  America.  The  young  are 
not  like  the  adult. 


Fig.  179. — Small-mouthed  black  bass  (Micrup'tcrus  dolomieu).     (Bull. 
U.  S.  F.  C,  1900.) 

The  sticklebacks  are  found  in  both  North  America  and  Europe.  They 
derive  their  name  from  their  formidable  dorsal  spines.  They  are  small 
marine  or  fresh- water  fishes. 


Sub-order  Pharyngog'nathi  includes  the  Wrasses  and  "flying- 
fishes."  The  pectoral  fins  of  flying-fishes  (Fig.  180)  are  large, 
and  serve  as  parachutes  when  the  fishes  leap  from  the  water. 

Sub-order  Plectog'nathi. — To  this  group  belong  the  file-fishes, 
which  are  often  protected  by  plates  or  spines,  and  in  shape  are 
very  deep  and  thin.     They  are  common  from  Cape  Cod  to  Cuba. 

Here  also  belong  the  trunk-fishes,  which  are  enclosed  in  a 
"box"  made  up  of  bony  plates  or  scales,  the  tail,  mouth,  and  fins 
being  movable. 

The  porcupine  fishes  are  covered  with  sharp  spines.  The 
Gymnodon'ta  or  "swell-fishes"  can  inflate  their  bodies  into  spheric 
sacs.     Their  flesh  is  poisonous. 

Sub-order  Lophobran'chii. — These  fishes  are  covered  with 
rings  of  large  plates.     They  have  club-shaped  tufted  gills,  no 


TP^LEOSTOMI  217 

pelvic  fins,  and  a  rudimentary  tail  fin.     The  mouth  is  at  the  end 
of  a  long  muzzle. 

The  pipe-fish  resembles  the  seaweed  and  has  the  power  of 
changing  color  to  suit  its  environment.  It  feeds  upon  small 
Crustacea  knd  moUusca.  It  is  found  on  Ijoth  European  and 
American  shores. 


Fig.  180. — Exonautcs  gilhcrti.     Type.      (Bulletin  .546,  U.  S.  Fish  Commis- 
sion.) 

The  sea-horse  (Fig.  181)  has  the  muzzle  at  nearly  a  right 
angle  with  the  rest  of  the  trunk,  giving  it  a  fanciful  resemblance 
to  the  head  of  a  horse.  It  swims  slowly  by  means  of  its  dorsal 
fins.  It  wraps  its  slender  curling  tail  about  seaweeds  and  roots, 
and  thus  avoids  being  transported,  unless  perchance  the  seaweed 
is  floating,  when  the  fish  is  carried  far  away  from  its  birthplace. 
It  resembles  the  seaweeds  among  which  it  lives — an  Austra- 
lian species  having  reddish  streaming  filaments  resembling 
plants. 

Economic  Importance. — Fishes  have  been  of  great  value  since 
primitive  times,  liut  the  various  methods  of  preserving  them  by 
drying  and  canning  has  greatly  added  to  their  importance,  for 
they  can  now  be  shipped  to  any  part  of  the  world.  Prol^ably 
salmon,  cod,  and  herring  are  of  the  greatest  value.  The  lake 
and  river  trout,  the  white  fish,  catfish,  the  black,  white,  and 
rock  bass,  and  the  perches  are  important  fresh-water  fishes, 


218 


BRANCH  C'HORDATA 


though  there  are  scores  of  others.     The  value  of  the  annual  out- 
put of  our  streams  and  coasts  is  at  least  $50,000,000. 

Each  nation  reserves  all  fishing  rights  within  three  miles  of  its 
coasts.  Outside  of  this  the  sea  fishes  are  open  to  the  world. 
The  largest  sea  fisheries  are  those  of  the  Atlantic  coast  of  the 
United  States,  Canada,  and  Newfoundland,  and  next  in  import- 
ance are  those  of  northern  Europe.  Thousands  of  fishermen 
from  the  United  States,  Canada,  and  France  are  engaged  in  the 
cod-fishing  on  the  foggy  banks 
of  Newfoundland,  whose  shallow 
waters  furnish  an  abundance  of 
food  for  the  cod,  and  make  these 
the  greatest  cod-fisheries  in  the 
world.  The  fisheries  along  our 
New  England  coast  supply  most 
of  the  fresh  cod-fish  for  our  home 
use.  Gloucester  is  the  largest 
fishing  port  of  the  United  States 
and  supplies  a  large  part  of  the 
salted  cod-fish  for  our  use.  "The 
Columbia  and  other  rivers  of  our 
northwest  coast,  including  Alaska, 
furnish  our  largest  salmon  fisher- 
ies. The  salmon  canning  industry 
of  Alaska  is  said  to  be  the  largest 
of  the  world." 

The  demand  for  this  whole- 
some food  product,  together  with 
recklessness,  has  caused  the  de- 
struction of  certain  species  in 
many  waters.  To  prevent  their  extermination  the  United 
States  Government  has  a  Bureau  of  Fisheries  which  has  es- 
tablished fish-hatcheries  in  almost  all  the  states.  In  these  the 
spawn  are  cared  for  until  they  hatch,  and  when  old  enough  the 
young  fishes  are  shipped  to  various  localities  for  stocking  ponds 
and  streams;  or,  the  eggs  themselves  may  be  distributed.  The 
food  supply  of  these  fishes  is  also  protected  or  introduced,  and 
their  enemies,  diseases,  and  life  histories  are  studied.  The 
annual  distribution  of  eggs  and  young  fishes  numbers  more  than 


Fig.  181. — Sea-horse  {Hippo- 
cam' pus  harhouri).  (Bull.  U.  S 
F.  C,  1907.) 


TELEOSTOMI  219 

a  billion  and  a  half.  Efforts  are  made  to  rid  the  streams  of 
voracious  fishes,  such  as  the  pike,  pickerel,  and  muscalonge, 
which  feed  upon  our  food  fishes. 

Besides  being  used  for  food,  fishes  furnish  other  useful  prod- 
ucts. The  skin  of  the  "dog-fish"  (shark)  is  used  as  leather,  and 
shagreen.  The  bodies  are  used  as  guano  or  fertilizer.  Oil  is 
obtained  from  the  menhaden,  cod,  and  other  forms.  Caviare 
is  a  preparation  of  the  salted  roe  of  sturgeons,  the  preparation  of 
which  constitutes  an  important  industry  on  the  Black  and  Cas- 
pian Seas.  Scales  of  some  species  are  used  in  ornamental  work, 
and  the  teeth  of  sharks  are  used  as  weapons  by  Pacific  Islanders. 
The  swim-bladders  of  cod-fishes  are  used  in  making  isinglass. 
They  are  also  pickled  and  eaten  under  the  name  of  "sounds." 

Geologic  Distribution. — Teeth  of  the  true  fishes  have  been 
found  in  the  Ordovician  of  Europe.  The  remains  of  sharks  prove 
their  existence  in  the  Silurian.  Fishes  are  found  in  great  variety 
and  abundance  in  the  Devonian  Period,  the  sharks,  lung-fishes, 
Crossopterygii  and  the  Ganoids,  the  most  advanced,  are  repre- 
sented. The  bony  fishes  (Teleosts)  are  entirely  absent  in  the 
Devonian.  These,  according  to  Scott,  are  approximated  by 
some  of  the  Jurassic  fishes.  In  the  Cretaceous  Period,  Ganoids 
become  rare  and  Teleosts  take  the  dominant  place  among  fishes. 
Marine  and  fresh-water  fishes  assume  the  modern  forms  in  the 
Eocene  Epoch. 

Important  Biologic  Facts. — The  skull  is  a  continuation  of 
the  vertebral  column,  and  contains,  but  is  not  filled,  by  a  genu- 
ine brain.  The  vertebrae  are  amphicoelous,  that  is,  concave  at 
each  end.     The  true  fishes  have  true  jaws. 

They  have  a  closed,  though  an  incomplete  circulation. 
The  blood-corpuscles  are  red. 

The  multiplication  is  sexual,  but  the  eggs,  or  roe,  are  ferti- 
lized in  the  water. 

The  skin  of  vertebrates  is  distinguished  from  that  of  inverte- 
brates by  the  many  layered  condition  of  the  epidermis  and  the 
thickness  of  the  dermis.  The  scales  of  fishes  are  of  dermal  origin 
and  different  from  the  epidermal  scales  of  reptiles.  It  is 
from  the  dermal  scales  that  the  bony  plates  of  turtles  and 
armadillos  have  arisen,  as  well  as  the  secondary  or  membrane 
bones. 


220 


BRANCH    CHORDATA 


The  strange  development  or  change  of  the  flounder  from  a  sym- 
metric to  a  "flat"  fish  demonstrates  the  principle  that  special 
habits  of  life  result  in  special  modifications  of  structure  which 
fit  the  animal  for  those  habits. 

The  lung-fishes  (Dipnoi)  show  many  advancements  toward 
the  air-breathing  conditions,  such  as  the  swim-bladder  used  as 
a  lung  and  the  partly  separated  auricle,  and  the  flipper  with  a 
central  axis  rather  than  a  fin,  so  that  zoologists  are  led  to  be- 
lieve that  they  may  represent  the  division  of  fishes  from  which 
the  amphibians  sprang. 

Classification. — 


Sub-phylum  Vertebrata  or  Craniata. 

Class    I.  Cyclostom'ata. 

Order    I.  Petromyzon'tes. 
Order  II.  Myxinoi'dei. 

Class  II.  Pis'ces. 

Sub-class  I.  Elasmobran'chii. 
Order     I.  Cladosela'chea. 

Order    II.  Pleuracan'thea. 
Order  III.  Sela'chii. 


Lamprey,  hag-fishes. 

Lamprey. 

Hag-fishes. 


Sub-class    II.  Holoceph'ali. 

Sub-class  III.  Dip'noi. 

Order      I.  Monopneu'mona. 
Order    II.  Dipneu'mona. 

Sub-class  IV.  Teleos'tomi. 

Order     I.  Crossopteryg'ii. 

Order    II.  Chondros'tei. 

Order  III.  Holos'tei. 

Order  IV.  Teleos'tei. 


Extinct  shark-like  forms. 

Cladoselache. 
Extinct  Pleuracanths. 
Extinct  forms  and  all  the 

living   Elasmobranchs, 

as  sharks  and  rays. 
Three  genera  of  Chimce- 

ridce. 

Ceratodus. 

Protopterus  and  Lepidosi- 
ren. 


AMPHIBIA 


221 


CLASS  III.     AMPHIBIA 

To  this  class  belong  the  toads,  frogs,  sala'manders,  and 
newts.  The  skin  is  smooth,  as  in  the  frog,  or  warty,  as  in  the 
toad,  with  a  glandular  secretion.  "One  group,  however,  possesses 
minute  scales,  but  some  of  the  extinct  Amphibia  were  provided 
with  well-developed  bony  plates  in  the 
integument." — Weysse.  It  is  often 
highly  colored  owing  to  the  pigment 
cells  in  the  deep  layers.  In  the  com- 
mon "tree-toad,"  as  well  as  in  some  of 
the  terrestrial  frogs,  the  color  may  be 
changed  to  harmonize  with  the  en- 
vironment. No  amphiljians  are  ma- 
rine. Most  of  them  are  aquatic  or 
semi-aquatic.     In  the  adult  stage  some 


Fiji.   1S2.— Hullfros.      (Skeleton  Fig.  l8S.—  Necturm.     (Skeleton 

cleaned  and  mounted  by  stu-  cleaned  and  mounted  by  stu- 
dents.) dents.) 

are  terrestrial,  some  arboreal.  They  are  usually  carnivorous  in 
the  adult  stage,  but  the  larva;  may  be  herbivorous.  They  hiber- 
nate in  the  mud  at  the  l.)ottom  of  a  stream  and  may  live  a  long 
time  without  food.  They  make  fine  specimens  for  study  in  a  tank 
or  tub,  since  many  of  them  will  endure  captivity  a  good  while. 


222 


BRANCH  CHORDATA 


Fig.  184. — Anatomy  of  common  frog:  My,  mylohyoid;  sr,  sternoradials ; 
th,  thyroid;  lu,  lungs;  /,  fat-body;  Te,  testis;  St,  stomach;  Sp,  spleen;  R, 
rectum;  a,  adductor  longus;  j»ot,  vastus  internus;  r»s,  sartorius;  n',  rectus 
internus  major;  ia,  tibialis  anticus;  g,  gastrocnemius;  ri",  rectus  internus 
minor;  a",  adductor  magnus;  rab,  rectus  abdominalis;  B,  bladder;  vd,  vas 
deferens;  b,  gall-bladder;  Ki,  kidney;  pv,  portal  vein;  Li,  liver;  V,  vena 
cava  inferior;  Ao,  aorta;  S,  vocal  sac  or  croaking-bag.  II.  Origin  of  the 
arterial  trunks:  I,  Arteria  ingualis;  eg,  carotid  gland,  which  is  merely  a 
rete  mirabile;  cr,  carotid  artery;  Ao,  aortic  arch;  Pa,  pulmonary  artery. 
III.  Dorsal  view  of  muscles  of  hind  leg:  gl.  Gluteus;  ra,  rectus  anterior; 
p,  pyriformis;  ve,  vastus  externus;  sm,  semimembranosus;  b,  b,  biceps;  g, 
gastrocnemius;  per,  peroneus.  (From  drawing  by  C.  S.  Minot.)  (From. 
Packard's  "  Zoology,"  Henry  Holt  &  Co.,  Publishers.) 


AMPHIBIA  223 

The  Skeleton. — There  are  two  occipital  condyles.  The  ver- 
tebrse  of  the  lower  forms  are  like  those  of  fishes,  biconcave; 
those  of  higher  Amphibia  are  usually  concavoconvex.  A 
sternum  first  appears  in  this  class,  as  well  as  a  typical  vertebrate 
limb-skeleton.  The  pelvic  girdle  is  united  with  the  spinal  col- 
umn. There  may  be  four,  two,  or  no  limbs,  that  take  the  place 
of"  fins.  They  have  digits  which  are  generally  without  claws.^ 
The  tail  is  temporary  in  frogs  and  toads  and  permanent  in 
other  amphibians.  Teeth  are  present  in  most  amphibians,  but 
lacking  in  the  toad.  They  are  small,  sharp,  and  point  back- 
ward. 

Respiration. — Amphibians  breathe  by  gills  in  the  larval  or 
tadpole  stage,  and  in  the  adult  forms  by  persistent  gills  or  by 
persistent  gills  and  lungs,  as  in  Necturus,  or  by  lungs,  as  in  the 
salamander.  The  skin  is  also  an  important  organ  for  taking  in 
oxygen  and  giving  off  impurities.  The  frog  breathes  with  the 
mouth  shut,  by  lowering  the  tongue  and  taking  in  air  through 
the  nostrils,  then  raising  the  tongue,  closing  the  nostrils,  and 
forcing  the  air  into  the  lungs. 

Circulation  (Fig.  184). — Amphibians  are  poikilothermal.  The 
heart  has  one  ventricle  and  two  auricles.  The  arteries  carry  the 
blood  to  all  parts  of  the  body.  The  veins  from  the  lungs  return 
the  pure  blood  to  the  left  auricle,  and  those  from  the  body  return 
the  impure  blood  to  the  right  auricle.  The  auricles  contract 
and  force  both  pure  and  impure  blood  into  the  ventricle,  which 
forces  it  out  in  such  a  manner  that  the  venous  blood  goes  to  the 
body  and  the  pure  blood  to  the  head.'' 

The  Nervous  System  (Fig.  185). — The  brain  of  a  frog  has 
advanced  alcove  that  of  the  fish  in  the  development  of  the  cere- 
brum, but  the  cerebellum,  which  is  very  small,  l^eing,  in  fact, 
but  a  thin  lamella,  is  inferior  to  that  of  the  fish. 

The  skin  on  the  whole  surface  of  the  body  is  provided  with 
tactile  nerve-endings,  and  contains  numerous  glands  which 
keep  it  moist  while  out  of  the  water.  Special  taste  organs  are 
located  on  the  tongue  and  mouth.  In  adult  amphibians  the 
nostrils  open  into  the  mouth,  and  Baskett  says,  "there  is  much  in 
the  arrangement  of  the  mucous  membrane  of  the  frog's  nose 
which  implies  that  it  smells."    The  strong  odors  of  some  of  their 

1  See  "Amphibia  and  Reptiles,"  Gadow,  p.  146. 

2  Linville  and  Kelly's  "General  Zoology,"  p.  330. 


224 


BRANCH    CHORDATA. 


excretions  would  also  imply  a  sense  of  smell,  but  these  may  be 
wholly  for  defense.     The  nostrils  ^  of  toads  and  frogs  can  be 

closed  by  special  muscles. 

The  lateral  line  of  the  tad- 
pole disappears  in  the  adult.  It 
seems  that  whatever  senses  may 
be  located  in  the  lateral  line, 
they  are  ineffectual  outside  of 
water. 

In  most  amphibians  there  is 
an  internal  ear  which  opens  by 
one  or  two  openings  into  the 
mouth,  back  of  the  openings 
from  the  nostrils.  None  of  them 
have  any  outside  opening  to  the 
ear,  but  most  of  the  higher  forms 
(Anura)  have  a  drum-cavity  and 
a  tympanic  membrane  over  it, 
lying  at  the  surface.  A  single 
bone,  the  columella,  lies  across 
the  middle  ear  and  has  one 
end  against  the  tympanum. 
There  is  no  cochlea,  or  at  least  a 
very  rudimentary  one;  hence  it 
does  not  seem  possible  that  the 
frog  can  detect  differences  in 
pitch.  Perhaps  this  accounts  for 
his  monotonous  song.  Yerkes 
found  that  frogs  "straightened 
up  and  raised  the  head  as  if  list- 
ening when  other  frogs  croaked 
or  splashed  into  the  water,"  but 
found  it  impossible  to  make  them 
res]5ond  in  any  way  to  any  noise 
he  himself  made  so  long  as  he 
remained  invisible.^  He  thinks 
they  depend  on  sight   for   the 


Fig.  185. — Brain  and  spinal  cord 
of  frog  (x  about  2):  a,  Cerebral 
hemisphere;  b,  olfactory  lobe;  c, 
eye;  d,  thalamencephalon ;  e,  optic 
lobes;  f,  cerebellum;  g,  medulla 
oblongata;  h,  fourth  ventricle;  i, 
spinal  cord;  I,  Olfactory  nerves; 
II,  optic  nerve;  III,  oculomotor 
nerve;  IV,  patheticus;  V,  fifth 
nerve;  VII,  facial  nerve;  VIII, 
auditory  nerve;  IX,  glossopharyn- 
geal nerve;  X,  vagus  nerve;  1-10, 
first  to  tenth  spinal  nerves;  2  and 
3  unite  to  form  the  brachial,  and 
7,  8,  and  9,  to  form  the  sciatic 
plexus.      (Shipley  and  McBride.) 


1"  There  seems  to  be  no  experimental  proof  of  specific  taste  or  smell 
among  amphibians  or  reptiles." — Washburn.  ^  Linville  and  Kelly. 


AMPHIBIA  225 

knowledge  of  danger.  Romanes  records  an  instance  of  a  pel 
frog  which  would  come  when  his  name,  "Tommy,"  was  called, 
no  matter  at  what  time  of  day,  though  fed  only  at  morning,  and 
another  instance  of  a  toad  kept  as  a  pet  for  thirty-six  years, 
which  knew  all  of  his  friends.  In  either  case,  the  knowledge 
might  have  been  gained,  at  least  in  part,  by  sight. 

The  eye  has  no  lids  in  the  lower  forms,  and  is  degenerate  in 
the  Pro' tens,  which  lives  in  caves  (see  Fig.  189),  and  in  some 
Gymnophi'ona.  Most  of  the  Anura  have  an  upper  lid,  but  no 
lower  one.  There  are  no  tears.  The  "flying  tree-toad"  has 
large  owl-like  eyes  (see  Fig.  195),  so  that  it  can  see  as  i'ar  as  it 
leaps.  Frogs  are  able  to  project  the  eyes  upward  to  give  greater 
range  of  vision.  When  the  mouth  is  inflated  the  eyes  are  pushed 
forward,  since  there  is  no  partition  between  the  eyes  and  mouth. 
It  is  well  known  by  boys  that  frogs  recognize  bright  colors,  and 
it  has  been  proved  by  experiment  that  they  can  distinguish  red 
from  white. 

Development. — The  eggs  of  Anura,  which  consist  of  the 
yolk  enclosed  in  a  mass  of  jelly-like  matter,  are  not  surrounded 
by  a  shell.  They  are  usualy  deposited  in  masses  (frogs)  or  in 
strings  (toads),  and  then  left  to  hatch  by  the  heat  of  the  sun. 
The  little  tadpole  has  a  small  sucking  mouth  and  a  slender  active 
tail.  The  branched  gills  soon  grow  out  on  the  sides  of  the  neck, 
but  are  later  replaced  by  internal  gills,  when  the  water  passes 
in  through  an  opening  on  each  side  of  the  neck.  The  tail  is 
gradually  absorbed,  the  legs  develop,  the  holes  on  the  sides  of  the 
neck  close,  and  the  limbs  develop  underneath  the  skin,  the  hind 
legs  coming  out  first  in  the  frog  forms,  but  in  all  others  it  is  the 
fore  limb  that  first  shows. ^  Meanwhile  "the  tadpole  ceases  to 
feed,  the  whole  intestinal  canal  is  voided  of  its  contents,  and,  by 
histolysis,  is  entirely  rebuilt,  becoming  wider  and  shrinking 
to  about  one-sixth  of  its  original  length,  undoing  thereby  the 
spiral,  preparatory  for  the  coarser  food,  which  consists  of  in- 
sects, worms,"-  and  any  live  animals  it  can  capture. 

Care  of  the  Young. — Usually  the  parents  take  no  care  of  the 
young,  but  there  are  some  interesting  exceptions.  The  little 
South  American  frog  {Rhinoder'ma  dar'wini)  carries  the  eggs  in 

'  Baskett,  "  Story  of  the  Amphibians  and  Reptiles,"  p.  34. 
2  Gadow,  p.  61. 


226 


BRANCH  CHORDATA 


the  immense  vocal  sacs  of  the  male  until  they  are  hatched.  A 
tree  frog  ( Hylo'des  linia'tus)  of  Dutch  Guiana  carries  its  young, 
which  cling  by  sucking  disks,  upon  its  back.  The  "Surinam 
toad"  (Fig.  186)  places  the  eggs  upon  the  back  of  the  female, 
where  the  skin  is  soft  and  spongy,  during  the  breeding  season. 
Each  egg  sinks  down  and  is  covered  by  a  jelly-like  film.  They 
remain  embedded  here  until  the  tadpole  stage  is  passed.  The 
pouched  frog  ( Nototre'ma  mar supia' turn)  has  the  eggs  stored  in  a 
pouch  on  the  back,  where  they  hatch  and  the  larvae  develop. 
The  male  of  the  European  species  {A'lytes  obstet'ricans)  winds  the 


Fig.    186. — Surinam    toad,    showing    young    escaping.     (From    Holder's 
"  Elements  of  Zoology,"  American  Book  Co.,  Publishers.) 


string  of  eggs  about  the  thighs  and  body.  A  Japanese  frog 
makes  a  nest  on  the  ground.  One  in  Brazil  makes  circular  nests 
in  shallow  water,  smoothing  and  shaping  rings  of  mud  and  laying 
the  eggs  in  these  cup-like  depressions.  Many  amphibians  are 
viviparous.^ 

Defense. — Almost  all  amphibians  are  more  or  less  poisonous, 
says  Gadow.  It  has  been  proved  that  if  a  quantity  proportion- 
ate to  the  size  of  the  animal  be  injected,  that  the  poison  secreted 
by  toads,  salamanders,  and  newts  will  kill  mammals,  birds,  rep- 
tiles, and  fishes.  The  poison  acts  upon  the  heart  and  central 
1  Baskett,  see  "Viviparous  Ajnphibians." 


AMPHIBIA  227 

nervous  system.^  The  Indians  of  Columbia,  it  is  said,  use  the 
secretion  of  Dendroh'ates  tindo'rius  for  poisoning  arrows  to  shoot 
monkeys.  That  this  secretion  protects  these  amphibians  from 
their  enemies  (the  ''glass  snake"  is  an  exception)  is  evident  from 
the  fact  that  "a  clog  that  has  once  been  induced  to  bite  a  toad 
suffers  so  severely  that  it  will  not  repeat  the  experiment."  The 
handling  of  the  tree-frogs  irritates  both  nose  and  eyes.  Many 
of  the  most  poisonous  amphiljians  (as  Salaman'dra  maculo'sa, 
Bom'hinator,  and  Dendroh'ates)  are  conspicuously  marked  with 
yellow  and  black.  The  horned  frog  of  South  America,  which 
fights  and  poisons  its  antagonist,  is  brilliant  in  green  and  gold. 
Many  assume  a  threatening  attitude.  "  Toads  normally  have 
the  sections  of  the  breast-bones  overlapping,  so  that  they  can 
swell  themselves  enormously  when  angry. "^ 

Ec'dysis. — All  amphibians  shed  the  epidermis.  The  first 
ecdysis  occurs  at  the  time  the  metamorphosis  is  completed, 
preparatory  to  terrestrial  life.  The  Anu'ra  roll  up  the  cast-off 
skin  and  swallow  it.  The  Urode'la  also  eat  it.  The  skin  of  the 
Anura  generally  splits  down  the  back,  but  that  of  the  Urodela 
breaks  loose  around  the  mouth,  and  the  animal  slips  out,  turn- 
ing its  hide  wrong  side  out.  So  long  as  growth  continues,  the 
skin  must  be  shed  often,  as  this  outside  layer  will  not  ''give" 
to  make  room  for  growth.  The  adult  Urodela  do  not  molt 
often,  but  usually  at  the  breeding  season,  when  they  go  to  the 
water  to  deposit  their  eggs.  The  Anura  molt  frequently,  at 
least  every  few  months,  probably  to  keep  the  skin  moist. 

Voice. — Most  of  the  Anura  and  some  of  the  Urodela  have  a 
voice  produced  by  the  larynx,  which  is  often  provided  with  a 
complicated  cartilaginous  and  muscular  apparatus  and  with 
vocal  cords.  The  female  of  the  Anura  is  mute  or  utters  only  a 
grunt.  The  sound  made  by  the  male  is  called  a  croak.  The 
voice  of  Urodela  is  a  feeble  squeak.  The  song  of  frogs  and  toads 
is  usually  of  the  nature  of  a  serenade  to  its  would-be  mate,  for 
they  do  not,  as  a  rule,  cry  out  in  fright  nor  in  rage.  A  notable 
exception  is  that  of  the  vicious  horned  frog  of  South  America, 
which  is  said  to  defy  its  foes  with  a  sort  of  bark,  but  which  has  a 
clear  bell-like  tone  for  its  friends.      Our  common  green  frog  is 

1  Gadow,  "  Amphibia  and  Reptiles,"  p.  38. 

2  Baskett,  p.  29. 


228  BRANCH    CHORDATA 

also  an  exception.  That  cloudy  or  damp  weather  has  some 
effect  in  making  certain  species,  as  the  tree-frogs,  sing,  is  per- 
haps explained  by  the  fact  that  the  skin  of  amphibians  is  used  as 
a  breathing  organ  as  well  as  for  a  body  covering,  and  it  must  be 
kept  moist  to  l)e  serviceable. 

Influence  of  Temperature. — Amphibians  living  in  the  water 
assume  its  temperature,  which  varies  much  from  noon  to  mid- 
night, and  from  the  stream  in  open  sunshine  to  the  cool,  shady 
spring.  According  to  Gadow,  ''most  Anura  die  when  their  tem- 
perature rises  to  40°  C,"  but  those  outside  of  water  in  open  air 
endure  greater  heat  than  aquatic  ones,  since  the  evaporation  of 
the  moisture  from  their  skin  lowers  their  temperature.  Most 
of  them,  and  especially  the  drier  skinned  toads,  seek  the  cool 
shade  or  even  estivate  during  the  hottest  part  of  the  summer. 
Many  of  them,  unless  they  are  used  to  tropical  climates,  can  en- 
dure a  very  great  amount  of  cold,  their  temperature  sometimes 
falling  to  the  freezing-point  during  hibernation.  Our  spotted  sal- 
amander, in  a  jar  of  water  out-doors,  was  forgotten  one  severely 
cold  night,  when  the  water  about  it  froze  solid.  It  was  put  into 
a  cool  room  and  allowed  to  thaw  gradually  as  the  weather  moder- 
ated, after  which  the  salamander  seemed  to  be  as  active  as  ever. 
Of  course,  the  animal  was  not  sawed  into  parts  to  find  out  if 
it  was  frozen  solid,  but  it  surely  looked  solid  enough.  It  does  not 
seem  possible  that  the  heart  was  absolutely  frozen,  for  the  heart 
"must  not  itself  be  frozen  if  the  animal  is  to  have  a  chance  of 
recovery."^ 

CLASSIFICATION     OF    AMPHIBIA 

Orderl.  Stegoceph'ala. — This  is  an  extinct  order  of  amphibians, 
described  by  Scott  as  animals,  which  have  a  skull  "well  covered 
with  a  roof  of  sculptured  bones  and  which  are  of  moderate  or 
small  size,  not  exceeding  7  or  8  feet  in  length  and  mostly  much 
smaller.  The  backbone  is  not  ossified,  the  limbs  are  weak,  the 
tail  short  and  broad,  and  in  many  forms  the  belly  is  protected 
by  an  armor  of  bony  scutes. "^  Most  of  them  were  like  sal- 
amanders in  shape,  but  some  were  long  and  snake-like. 

Order  II.  Ap'oda  or  Gymnophi'ona. — This  group  comprises 

one  family  of  limbless,  tailless,  vermiform,  subterranean  am- 

1  Gadow,  p.  68. 

^  Scott,  "  Introduction  to  Geology,"  p.  427. 


CLASSIFICATION    OF    AMPHIBIA  229 

phibians  of  the  tropical  regions  which  burrow  in  the  ground  and 
feed  on  worms  and  insect  larvse.  They  have  from  two  hundred 
to  three  hundred  vertebra?.  There  are  no  gills  or  gill-slits  in  the 
adult  stage.  Their  mode  of  locomotion  is  much  like  that  of  the 
earthworm.  It  is  produced  by  the  peristaltic  motion  of  the 
skin,  aided  by  the  numerous  ring-shaped  constrictions.  The 
eyes  are  vestigial  and  concealed  beneath  the  skin. 

The  only  family  is  CoBcili'idoe,  with  some  forty  species.  Some  }i;onera, 
as  Ichthyophis,  have  small  scales  embedded  in  the  skin.  Others,  ns  the 
Typhlonectes  of  Guiana  and  Venezuela,  are  scaleless.  T.  coinprrssiatuda 
is  18  inches  long  and  f  inch  in  diameter.  Its  color  is  from  an  olive  brown  to 
black,  which  is  the  general  color  of  most  species.  Some,  as  Ichthyophis,  are 
oviparous;  others,  as  Dermoplds,  are  viviparous. 

Order  III.  Urode'la  or  Cauda'ta. — These  are  the  tailed  and 
limbed  amphibians.     They  have  four  limbs,  as  in  the  toads  and 


Fig.  187. — Siren  (5t'/c/(  Imuii'iia)       (C'hapin  and  Rettger,  Englehard  & 
Co  ,  Pubhbhers.) 

frogs;  or  two,  as  in  the  Siren.  The  skin  is  smooth  and  slimy. 
Locomotion  is  accomplished  mostly  by  body  motion,  aided  by 
the  weak  limbs,  in  strong  contrast  with  the  limb-motion  of  the 
frogs  and  toads.  They  are  not  very  common  as  compared  with 
frogs  and  toads.     Newts  and  salamanders  are  examples. 

Siren'idcB  is  a  small  family  of  two  genera  of  one  species  each.  The 
"mud-eel"  {Siren  lacertina)  (Fig.  187)  of  the  southern  United  States  is  2  or 
3  feet  long.  Posterior  limbs  are  wanting,  and  the  weak  anterior  limbs  have 
four  digits.  The  tail  is  long,  compressed,  and  thin.  There  are  three  pairs 
of  gills,  but  they  atrophy  in  the  young  and  are  redeveloped  subsequently. ^ 
The  mud-eel  is  a  harmless  creature,  burrowing  in  the  mud  of  ponds  and 
ditches.     Dorsally  it  is  dark    colored,  but  lighter  ventrally.      Sometimes 

1  Gadow,  p.  136. 


230 


BRANCH  CHORDATA 


it  is  spotted  with  small  white  specks.    When  swimming,  the  limbs  are  folded 
back. 

The  other  species  {Pseudobran'chus  dria'tus)  is  only  about  7  inches  in 
length  and  has  three  digits  to  each  fore  foot. 


Fig.   188.— IMud  pui 


111  and  lUttg(r,  Lnglc  hard  &  Co.,  Pub- 
lishers.) 


The  family  Prote'idm  consists  of  amphibians  having  three  pairs  of  per- 
sistent gills,  two  pairs  of  weak  limbs  with  four  digits  to  each  one,  or  the 


^     /^' 


Fig.  I'm.—Pw'ltui.  angutnus      Kuiop(       i,iuoni  Do(U(  >=    '  Giueral  Zool- 
ogy," American  Book  Co,  Publisheis  ) 


anterior  pair  with  two,  and  the  posterior  with  three  digits.  The  eyes  are 
without  lids  and  covered  by  a  transparent  skin,  but  are  functional.  They 
have  teeth  on  the  vomer,  mandible,  and  premaxillaries. 


CLASSIFICATION    OF    AMPHIBIA  231 

The  water-dog  or  mud-puppy  (Fig.  188)  ( Nectu'rus  macula'tus)  is  a  rather 
common,  clumsy  form  found  in  the  Mississippi  Valley  and  the  region  of  the 
Great  Lakes  and  east  to  the  Alleghenies.  They  are  nocturnal,  but  vora- 
cious, feeding  on  insects,  worms,  small  fish,  and  crustaceans.  Those  in 
our  laboratory  were  15  inches  long  with  dark  brown  spots. 

The  blind  Pro' teas  angui'nus  of  Europe  (Fig.  189)  belongs  to  this  family. 
It  is  white  and  lives  in  total  darkness  in  a  temperature  of  about  50°  F.  If 
brought  to  the  light  the  skin  will  ultimately  change  to  a  dark  color. 
There  is  a  similar  species  {Typhlomol'ge  rath'buni)  in  Texas. 

Family  Amphi'umidae. — These  animals  are  without  gills  in  the  adult 
stage.  They  ha\-e  teeth  in  both  jaws.  They  have  four  small,  weak 
limbs. 

The  hellbender  {Cryptobran'ckus  alleghanien'sis)  is  a  stout-bodied,  four- 
footed,  ugly,  but  harmless  amphibian,  which  is  sometimes  2  feet  in  length. 
It  is  brown  or  gray  above  and  lighter  below.  It  feeds  on  worms,  crayfish, 
fish,  and  such  other  creatures  as  it  can  obtain  in  its  aquatic  habitat.  It  is 
restricted  in  its  distribution  to  the  streams  of  the  mountainous  regions  of 
the  eastern  United  States. 


Fig.  190. — Congo  snake  (Amphiu'ma  me'ans).     (From  Holder's  "  Elements 
of  Zoology,"  American  Book  Co.,  Publishers.) 

The  giant  salamander  of  Japan  {C.  japon'tcus)  reaches  a 'length  of  4  to 
5  feet.  It  lives  in  small  streams  and  mountain  meadows  of  Japan  and 
China,  from  600  to  4500  feet  above  sea-level.  Sasaki  reports  that  it  lives 
singly,  lying  concealed  under  rocks,  in  swift,  thickly  shaded,  small,  clear, 
cold  streams.  It  feeds  on  animals  which  it  can  capture  in  the  water  and 
may  be  caught  with  a  fish-hook.     It  is  used  for  food  by  the  Japanese. 

The  "Congo  snake"  {Amphiu'ma  me'ans)  (Fig.  190)  is  eel-like,  with 
four  weak  limbs,  having  two  or  three  toes  each.  Its  general  color  is  black, 
with  lighter  under  parts.  It  attains  a  length  of  .3  feet.  It  lives  in  the 
swamps  and  rice  fields  of  the  southeastern  United  States.  It  feeds  on 
crayfish,  mollusks,  and  fislies.     It  is  quite  harmless. 

Fsim'Ay  S(il(iman'>/rl(hi ,  or  salamanders  and  newts,  are  our  most  common 
Urodela.  All  are  harmless,  and  are  generally  but  erroneously  called 
lizards.  They  have  no  persistent  gills.  They  have  two  pairs  of  weak 
limbs.  Nearly  all  have  movable  eyelids  and  teeth  in  both  jaws.  There 
are  twelve  or  fifteen  species  in  the  United  States. 


232 


BRANCH    CHORDATA 


The  spotted  salamander  {Amhlys'toma  puncln'tum)  is  our  common  species 
in  the  Mississippi  \'alley  (P'ig.  191).  It  is  darlc  brown  or  blackish  above, 
marked  with  about  thirty  irregular  yellow  spots.  It  is  found  in  wells  and 
cellars.     It  is  oviparous. 

One  species  {Amhlys'toma  tigri'num),  which  is  found  in  Mexico  and  Cali- 
fornia and  even  in  New  York  and  Minnesota,  affords  a  striking  example  of 
neoteny,^  or  the  "  more  or  less  complete  retardation  of  development,  or  the 
retention  of  partially  larval  conditions.'"'^  If  the  pond  in  which  this  axolotl, 
or  larva  (Fig.  192),  lives  begins  to  dry  uj),  its  gills,  fins,  and  tail  shrink,  and 
finally  disappear,  the  animal  begins  to  brcat  he  air,  and  gradually  becomes  a 
terrestrial  salamander.^  But  if  it  is  reared  in  deep  water  or  forced  by  deep 
walls  to  remain  in  aquatic  conditions,  the  larval  or  aquatic  gills  and  tail 
are  retained,  even  after  sexual  maturity  has  been  reached.  One  would 
think  this  was  a  forcible  proof  of  the  influence  of  environment  on  the 
development  of  the  individual,  but  the  strangest  part  of  it  is  that  it  is  said 


Fig.  191. — Common  yellow  spotted  salamander.     (Morse.) 

there  have  sometimes  been  found,  side  by  side  with  these  prolonged  larval 
individuals,  others  apparently  of  the  same  species  which  have  completed 
their  metamorphosis.^ 

The  newts  or  tritons  all  prefer  moisture  without  heat.  In  the  mating 
season  they  take  to  the  water,  undergo  various  changes,  and  become 
aquatic.  After  the  breeding  season  is  over,  they  become  terrestrial,  hiding 
in  cracks  or  in  the  sand.  Some  estivate  in  the  hot  dry  season.  They 
hibernate  usually  in  the  ground,  but  sometimes  in  ponds.  The  food  con- 
sists of  insects,  centipedes,  and  snails.  "  They  do  not  drink,  but  soak  them- 
selves in  water."^ 


»  Basket f  and  Ditmars. 

2  Parker  and  Haswell.  ' 

3  Linville  and  Kelly. 

*  Ilertwig  (p.  587,  Kingsley's  translation)  says  adults  of  true  axolotl  are 
unknown. 

5  Gadow,  p.  123. 


CLASSIFICATION    OF    AMPHIBIA 


233 


The  crimson-spotted  newt  (Tri'ton  virides' ccns)  is  abundant  in  northern 
and  eastern  states.  Aliove,'  it  is  greenish  brown,  with  two  rows  of  crimson 
spots.  Below,  it  is  orange,  with  black  dots.  It  lives  in  deeper  water  than 
is  usual  for  salamanders  and  "  swims  freely,  often  in  an  upright  position, 
with  hind  legs  hanging  motionless,  while  the  tail  does  all  the  work." 

Order  IV.  Anu'ra  or  Ecauda'ta. — "The  Anura  are  a  very  spe- 
cialized group.     Their  development  (see  p.  225)  indicates  their 


Fig.  192. — Axolotl,  a  creature  living  and  breeding  for  generations  in  the 
water.  Amblystoma  coming  out  of  the  water.  Amblystoma  breathes  by 
lungs,  having  lost  its  gills.  (From  Holder's  "  Elements  of  Zoology,'' 
American  Book  Co.,  Publishers.) 


derivation  from  branchiate,  tailed  forms,  but  there  is  no  paleon- 
tologic  evidence  on  this  point."' 

Aglos'sa. — This  group  is  characterized  by  the  absence  of  a 
tongue  and  by  a  common  opening  for  the  Eustachian  tubes.  It 
is  represented  by  the  Pijia  or  "Surinam  toad"  of  South  America 
(see  Fig.  186)  and  by  the  Dactyl' ethra  (Fig.  193)  of  Africa. 

1  Parker  and  Haswell,  p.  291. 


234 


BRANCH  CHORDATA 


Phaneroglos'sa. — This  group  is  characterized  by  the  presence 
of  a  tongue  and  by  distinct  Eustachian  tubes.  It  includes  the 
toads  and  frogs.  Gadow  estimates  900  species  in  the  world. 
Frogs  and  toads  have  tails  in  the  larval  or  tadpole  (Fig.  194) 
condition,  but  are  tailless  in  the  adult  stage.  The  body  is 
short  and  stout.  They  have  a  small  number  of  trunk  vertebrae 
and  the  caudal  vertebrae  are  replaced  by  one  long  bone,  the  uro- 
style.  They  have  four  limbs,  the  posterior  ones,  long,  strong,  and 
adapted  for  leaping  or  hopping.  Toads  are  crepuscular  and 
nocturnal.  They  hibernate  in  the 
mud  at  the  bottom  of  the  water. 
The  tadpole  or  "pollywog"  is 
fish-like  and  aquatic.  It  has  a 
long  tail  and  breathes  by  gills. 
Its  intestine  is  very  long,  adapt- 
ing it  to  its  vegetable  food. 

Family  Bufon'idae.  —  Toads  are 
clumsy,  stout-bodied,  nocturnal  insect- 
feeders.  The  tongue  is  fixed  by  the 
anterior  end  and  can  be  thrust  out  to 
catch  its  food.  They  have  no  teeth. 
The  skin  is  warty  or  glandular  and 
secretes  a  fluid  for  protection.  The 
toes  are  webbed,  but  not  dilated  at  the 
tips.  Toads  resemble  the  ground  very 
closely. 

The  American  toad  {Bu'fo  lentigino'- 
sus)  is  famiHar  to  all.  The  young  are 
nearly  smooth,  the  adults  warty.  They 
are  brownish-olive,  with  a  yellowish 
median  line  and  brown  spots.  There  is  a  bony  ridge  behind  and  above 
the  eye  ami  two  black  patches  below  the  eye.     The  tympanum  is  large. 

Family  Hy'lidae  or  Tree  Frogs. — These"  are  arboreal  frogs  with  an  op- 
posing thumb  and  with  adlicn-ing  disks  on  the  end  of  each  toe,  by  which 
they  cling  to  the  trees  in  which  they  live. 

Our  most  common  example  is  the  northern  tree-frog  ( Hy'la  ver'sicolor)  of 
the  eastern  United  States  and  Canada.  It  is  about  2  inches  long  and  deli- 
cately colored.  "  Its  color  passes  within  a  short  time  from  dark  brown  or 
olive  gray  to  pale  gray  or  white,  occasionally  retaining  a  few  large  dark 
patches  on  the  back  and  delicate  cross-bars  on  the  limbs."  It  has  small 
warts,  which  produce  an  acrid  secretion.  It  is  found  not  over  20  feet  from 
the  ground  in  trees  or  on  lichen-covered  stone  fences.  Its  color  renders 
it  almost  perfect  in  protective  resemblance.  One  may  be  within  a  foot  of 
it  and  not  be  able  to  distinguish  it.  It  croaks  noisily  in  the  evening  or 
just  before  a  rain.  In  croaking  its  vocal  sacs  swell  to  enormous  pro- 
portions.    It  remains  quiet  in  the  shade  during  the  day,  but  is  lively  in 


193. — DadyVethra   capen - 
sis.     (Claus.) 


CLASSIFICATION    OF    AMPHIBIA 


235 


Fig.  194. — The  metamorphosis  of  the  frog.      The  numbers  indicate  the 
sequence.     (Galloway  after  Brehm.) 


Fig.  195. — Flying  tree-toad  of  Borneo  {Rhacoph'orus).     (After  Wallace.) 


236  BRANCH    CHORDATA 

the  evening,  feeding  on  insects.  Gadovv  mentions  a  tree-frog  which  lived 
twenty-one  years. 

Family  Ran'idae. — Frogs  {RuniiKi:}  have  teeth  in  the  upper  jaw.  The 
toes,  four  to  five,  arc  more  or  less  \vcl)l)cd.     The  tongue  is  like  the  toad's. 

Our  largest  species  is  the  bullfrog  (Ra'na  catesbia'na) ,  which  measures 
from  5  to  8  inches.  It  is  known  by  its  deep  bass  voice.  It  has  two 
large  internal  vocal  sacs.  Its  toes  are  broadly  webbed.  In  color  it  is 
varying  shades  of  green  above,  with  faint  dark  spots,  the  head  is  bright 
green,  the  legs  blotched.  The  tympanum  is  large.  Its  hind  limbs  are 
much  prized  for  food.  Bullfrogs  are  solitary  except  in  the  breeding  season, 
when  hundreds  collect  in  the  same  small  pond.  They  are  commonly  found 
sitting  half  immersed  in  water,  or  waiting  for  their  prey  upon  the  banks 
of  a  pond.  The  bullfrog  is  voracious,  devouring  mollusks,  fishes,  and  frogs, 
as  well  as  ducklings  and  young  water  fowls.  It  is  eaten  by  fishes,  birds, 
otters,  snakes,  and  alligators. 

The  green  frog  {R.  clamafa)  is  a  brownish-green  color,  brighter  in  front, 
with  irregular  small  black  spots,  and  blotched  limbs.  Below,  the  color  is 
yellowish  white.  The  tympanum  is  large.  It  is  common  in  the  eastern 
United  States.     The  vocal  sacs  are  small  and  internal. 

Wallace  describes  a  species  of  Raniiln'  which  was  brought  to  him  in 
Borneo.  The  body  was  about  4  inches  in  length  and  the  webs  of  both  fore 
and  hind  feet  were  enlarged  and  used  as  parachutes  by  these  "  flying  frogs" 
(Fig.  195). 

Classification. — 

Order.  Examples. 

I.  Stegoceph'al'ia.  Extinct  forms. 

II.  Ap'oda  or  Gymnophi'ona.  Coeciliidse. 

III.  Urode'la  or  Cauda'ta.  Necturus,  Salamanders. 

IV.  Anu'ra  or  Ecauda'ta.  Frogs,  Toads. 


CLASS   IV.     REPTILIA 

This  class  of  Chordates  consists  of  snakes,  lizards,  turtles, 
crocodiles,  and  alligators,  together  with  a  number  of  extinct 
orders.  "Compared  with  the  ages  that  are  gone  the  reptile  life 
upon  our  globe  has  decreased  to  mere  parasitic  proportions." — 
Ditmars. 

Reptiles  are  scaly.  They  are  aquatic  or  terrestrial;  a  few 
are  arboreal.  There  is  one  occipital  condyle,  and  the  lower  jaw 
is  united  to  the  base  of  the  skull  by  a  quadrate  bone. 

The  limbs  are  four,  two  (the  Python  and  some  kindred  forms 
have  the  vestiges  of  the  hind  limbs  only),  or  none,  as  in  the 
"glass  snake"  and  our  common  snakes. 

Reptiles  are  poikilothermal.  The  heart  has  one  ventricle 
and  two  auricles,  except  in  order  Cro'codilia,  where  the  heart  has 
two  auricles  and  two  ventricles. 


REPTIl-IA 


^37 


Plica 
Semilunaris 


Fig.  196. — Illustrations  of  the  nictitating  membrane  in  the  various 
animals  named,  drawn  from  nature.  The  letter  N.  indicates  the  membrane 
in  each  case.  In  man  it  is  called  the  plica  semilunaris,  and  is  represented 
in  the  two  lower  drawings  under  this  name.  In  the  case  of  the  shark 
{Galeus)   the  muscular  mechanism  is  showir^  dissected.     (Romanes.) 


238  BRANCH    CHORDATA 

Reptiles  always  breathe  by  lungs.  "The  air  is  drawn  into 
the  lungs  of  snakes,  lizards,  and  crocodiles  by  the  play  of  the 
ribs."^ 

The  nervous  system  is  somewhat  more  highly  developed  than 
in  the  amphibians.  There  is  a  middle  and  an  inner  ear.  The 
eye  has  an  upper  and  a  lower  movable  eyelid  and  also  a  nicti- 
tating membrane  (Fig.  196).  True  nostrils  and  salivary  glands 
appear  first  among  the  reptiles. 

Reptiles  are  oviparous,  ovoviviparous,  or  viviparous.  There 
is  no  metamorphosis. 

In  ecdysis  the  skin  may  be  cast  in  one  piece,  as  in  all  snakes 
save  sea-snakes  and  in  most  lizards;  in  strips,  as  in  some  lizards; 
in  little  pieces,  as  in  the  western  horned  toads;  or  in  flakes,  as  in 
the  geckos.  Some  tortoises  shed  the  whole  outer  layer  of  epi- 
dermal shields  periodically. 

Gadow  briefly  defines  Reptilia  as  "monocondylia  with  a  scaly 
skin." 

Reptiles  live  longer  than  most  warm-blooded  animals.  A 
turtle  in  the  Zoological  Park,  New  York,  says  Ditmars,  is  esti- 
mated to  be  over  three  hundred  and  fifty  years  old. 

ORDER   I.     RHYNCHOCEPHALIA 

Rhynchocephalia  is  represented  by  Sphen'don  ptmcta'tum 
{Hatte'ria)  of  New  Zealand.  It  is  a  lizard-like,  four-limbed, 
pentadactyle,  nocturnal,  carnivorous  reptile  |  meter  in  length. 
"It  is  the  sole  remnant  of  an  order  long  extinct.  It  is  literally 
a  ghost  of  the  past,  the  oldest  surviving  type  of  reptile." — 
Ditmars. 

Its  color  is  dark  olive  green,  with  small  white  or  yellowish 
specks  on  the  sides.  Its  length  is  from  15  to  30  inches,  while 
fossil  forms  were  sometimes  6  feet  long.  A  row  of  spines  extends 
along  the  back.  Its  means  of  defense  are  biting  and  scratching. 
It  burrows.  It  lays  about  ten  hard-shelled  white  eggs  in  the 
sand.  Gadow  has  "come  to  the  conclusion  that  they  are  dull, 
not  companionable  creatures."    Their  sound  is  a  grunt  or  croak. 

For  an  interesting  description  of  this  living  fossil  read  Gadow, 
"Amphibia  and  Reptiles,"  pp.  294-300.  Look  at  the  picture  of 
the  skeleton  and  state  the  branch,  class,  and  ordinal  character- 
istics you  see, 

'  Dodge. 


OPHIDIA 


239 


ORDER   II.      OPHIDIA 

Snakes  are  considered  degenerate  lizards,  and  by  some  zo- 
ologists are  classed  with  the  lizards,  and  the  group  together 
called  Order  Squamata. 

The  Ophidians  are  reptiles  with  no  fore  limbs,  no  pectoral 
girdle,  no  sternum  or  sternal  ribs,  but  the  ends  of  the  dorsal 
ribs  are  connected  with  the  ventral  scales,  or  scutes,  and  both 


„      \ic;iT 
6    fr»/?Ay  TeK!<  mriofl  of 


Fig.  197. — Rudimentarj'  or  vestigial  hind  limbs  of  python  as  exhibited 
in  the  skeleton  and  on  the  external  surface  of  the  animal  {\  natural  size). 
(Romanes.) 


scales  and  ribs  aid  in  the  body  motion.  "A  snake  literally 
walks  on  the  ends  of  its  ribs." 

Vestiges  of  the  hind  limbs  (Fig.  197)  sometimes  appear  as  little 
spurs  on  either  side  of  the  vent.  The  ribs,  which  begin  with  the 
second  vertebra  and  continue  to  the  end  of  the  body,  aid  in  res- 
piration. They  aid  in  locomotion  also,  their  ventral  ends  fitting 
into  the  "connective  tissue  of  the  sides  of  the  ventral  transverse 
scales  (scutes) ."  The  body  is  long  and  the  vertebrae  very  numer- 
ous. 

They  vary  in  size  from  the  enormous  ones  of  the  tropics  to 
our  little  green  grass  snakes.     Some  are  aquatic,  some  terrestrial 


240  BRANCH    CHORDATA 

or  subterranean,  while  still  others  are  arboreal  in  their  habits  and 
habitat. 

The  color  of  snakes  is  usually  brownish  or  green,  which  affords 
a  good  protective  resemblance  to  the  ground  or  grass  upon  which 
they  creep. 

The  skin  is  scaly.  The  horny  epidermis  is  shed  from  one  to 
several  times  yearly,  the  whole  outer  skin,  from  lips  to  tail,  being 
turned  wrong-side  out,  even  to  the  transparent  covering  of  the 
eyes.  The  first  molting  takes  place  "within  forty-eight  hours 
after  birth"  before  the  young  snake  begins  to  feed.  In  the 
rattlesnake,  at  each  time  the  skin  is  shed,  "there  is  left  a  ridge 
or  rim  of  it  at  the  tail,  which  forms  the  rattle." 

Food. — Since  there  are  no  limits  for  prehension,  snakes  must 
depend  upon  the  mouth  to  secure  the  prey,  which  is  swallowed 
whole.  The  constrictors,  like  our  common  blue  racer  and  the 
boa  constrictor,  wind  their  bodies  about  their  victims  and 
literally  squeeze  them  to  death.  The  teeth  point  toward  the 
throat,  thus  preventing  the  escape  of  the  prey  from  the  mouth. 
The  snake  has  also  a  distensible  lower  jaw,  enabling  it  to  swal- 
low an  animal  as  large  or  larger  than  the  diameter  of  the  snake's 
own  body.  The  bones  and  palatal  apparatus  are  united  by 
ligaments  only,  thus  allowing  them  to  spread  apart  in  the 
process  of  swallowing.  An  abundant  supply  of  saliva  (which 
appears  first  in  reptiles)  renders  swallowing  the  more  easy. 

Snakes  are  carnivorous,  feeding  upon  mice,  birds,  frogs,  and 
insects.  Poisonous  snakes  should  l)e  killed,  of  course,  but  the 
non-poisonous  ones  are  quite  useful  in  the  fields  in  destroying 
vegetable-feeding  animals,  especially  rodents  and  insects. 

Respiration  is  mainly  by  one  lung,  the  other  one  being 
rudimentary.  The  trachea  may  be  slightly  protruded  between 
the  halves  of  the  lower  jaw  during  the  process  of  swallowing,  to 
prevent  suffocation. 

Senses  and  Intelligence. — The  eyes  are  not  movable  nor  have 
they  a  movable  eyelid,  hence  their  glassy  stare.  The  lacrimal 
fluid  passes  internally  into  the  nasal  cavities.  No  external  ear 
is  visible,  though  the  hearing  is  good.  The  sense  of  smell  is 
well  developed,  some  snakes  being  greatly  aided  by  it  in  their 
search  for  prey.  The  tongue,  which  is  slender,  forked,  and 
sheathed,  is  protractile,  moist,  and  very  sensitive  to  touch. 


OPHIDIA  241 

Snakes,  while  showing  considerable  intelligence,  are  seldom 
much  attached  to  their  keepers,  being  more  often  reticent  and 
surly. 

Multiplication. — The  eggs  of  snakes  are  not  hard  shelled, 
but  are  covered  with  a  tough  membrane.  Generally  the  snake 
loosely  buries  the  eggs  or  deposits  them  half-hidden  in  cracks 
and  crevices.  Many  snakes  are  ovoviviparous.^  The  young 
are  precocial.     Male  snakes  are  smaller  than  the  females. 

As  in  reptiles  generally,  the  number  of  young  at  a  litter  is 
large,  but  the  number  varies  with  the  species.  That  of  the 
poisonous  snakes  is  said  to  seldom  exceed  fifteen,  except  those 
of  some  of  the  tropical  ones.  Ditmars  mentions  a  boa  con- 
strictor in  captivity  which  "  gave  birth  to  sixty-four  fully  devel- 
oped young,  while  a  huge  python  deposited  seventy-nine  eggs, 
which  she  gathered  in  her  coils  and  guarded  jealously"  until 
hatched.  During  this  period  of  incubation  the  Ijody  tempera- 
ture is  raised.  Our  little  garter  snake  has  a  litter  of  about 
thirty-five,  while  that  of  the  common  water  snake  has  been 
known  to  number  sixty.  The  copperhead  has  about  eight  or 
nine  young. 

The  length  of  life  may  be  said  to  be  considerably  shorter  than 
that  of  the  chelonians  and  crocodilians,  as  growth  is  more 
rapid.  Adult  snakes  received  in  the  Zoological  Garden,  New 
York,  says  Ditmars,  have  been  kept  for  ten  years  without  show- 
ing signs  of  age,  and  pythons  even  fifteen  years.  The  snakes 
of  this  latitude  hibernate  in  caves  and  dens  or  in  deep  crevices 
between  the  rocks.  In  the  tropical  regions  some  species  esti- 
vate  in  summer. 

Defense. — Besides  their  protective  coloration,  snakes  are 
further  provided  with  several  means  of  defense.  Some  are 
protected  from  their  enemies  l^y  a  characteristic  odor,  while 
others  have  the  deadly  poison  fangs.  Another,  and  by  far  the 
most  common  means,  is  by  noiseless  flight.  A  few  species 
burrow  or  slip  into  holes  to  escape,  while  the  boa  constrictors 
squeeze  their  enemies  to  death.  Most  snakes  will  not  attack 
man  if  unmolested,  and  they  are  generally  as  much  frightened 
as  the  person  is.  They  charm  birds,  probably  by  paralyzing 
them  with  fear,  until  they  can  creep  up  to  and  catch  them. 
'  See  Glossary. 
16 


242 


BRANCH    CHOUDATA 


The  author  attracted  the  attention  of  a  charmed  bird  from  its 
gaze  ujion  the  snake  and  the  bird  innnediately  flew  away. 

The  poison  gland  is  an  especially  modified  salivary  gland,  and 
the  poison  fangs  are  maxillary  teeth  wliich  have  a  furrow  on  the 


Fig.  198. — A  case  of  mimicry,  where  a  non-venomous  species  of  snake  re- 
sembles a  venomous  one.     (Romanes.) 


anterior  side,  or  the  furrow  is  changed  into  a  canal  for  the  pas- 
sage of  the  poison  to  the  end  of  the  fang,  and  hence  to  the 
deepest  portion  of  the  wound,  where  it  poisons  the  blood  of  the 
victim.  Colton  gives,  as  an  antidote,  a  10  per  cent,  solution  of 
ammonium  carbonate  taken  internally. 


LACERTILIA 


243 


There  are  many  enemies  of  snakes.  Prominent  among  them 
are  kites,  hawks,  shrikes,  and  other  birds  of  prey,  hogs,  and 
man. 

Family  Colu'bridae  includes  all  our  common  harmless  snakes,  as  the 
garter  snake,  "  hoop  snake,"  water  snake,  green  snake,  black  snake  or 
blue  racer,  blowing  viper,  and  others.  They  are  all  perfectly  harmlesSj 
though  they  make  great  pretensions  with  their  terrifying  appearance  or 
bluff  as  to  what  they  might  do  if  you  came  too  close. 

Family  Crotaridae  includes  the  rattlesnake,  copperhead,  and  water 
moccasin.  All  of  these  are  poisonous  and  to  be  feared.  The  rattlesnake 
gives  warning,  not  so  the  deadly  copperhead  and  water  moccasin.  Hap- 
pily for  man,  civilization  is  driving  out  these  dangerous  reptiles. 

Family  Elap'idae  is  another  family  of  venomous,  chiefly  East  Indian, 
snakes.  There  is  one  species  (Fig.  198),  the  "bead  snake"  (Flaps  fvVvius), 
found  from  Virginia  to  Arkansas  and  south.  Jordan  describes  it  as  "jet 
black  with  about  seventeen  broad  crimson  rings,  each  bordered  with  yellow 
and  spotted  below  with  black,  a  yellow  occipital  band,  tail  with  yellow 
rings."  It  is  surely  an  example  of  warning  colors  which  one  will  do  well 
to  heed.     A  non-venomous  species  closely  resembles  it. 

Library  References. — Gadow's  "Amphibia  and  Reptiles" — Ophidia. 
Read  of  snakes  of  other  lands.  Baskett  and  Ditmar's  "  Story  of  Am- 
phibians and  Reptiles";  Parker  and  Haswell  on  "Reptilia";  Ditmars' 
"Reptiles  of  the  World." 


ORDER   III.      LACERTILIA 

Lizards  are  reptiles  with  a  distinct  head,  a  snake-hke  body,  a 
tail  generally  longer  than  the  body,  and  four  short,  nearly 


Fig.  199. — .Skeleton  of  a  lizard:  sp,  Spinous  processes,  which  in  the  tor- 
toise are  flattened  into  plates;  r,  ribs;  s,  shoulder-bone;  a,  upper  arm;  e, 
elbow;  fa,  forearm;  h,  hip-bone;  th,  thigh-bone;  k,  knee;  I,  bones  of  the 
leg;  q,  quadrate  bone  between  upper  and  lower  jaw.     (From  Holder.) 


equal  limbs,  or  no  functional  limbs,  as  in  the  so-called  "  glass 
snake  "  or  "  joint  snake."     Their  locomotion  is  aided  by  a 


244  BRANCH    CHORDATA 

wriggling  body  motion.  "  Two  aortic  branches,  a  left  and  a 
right,  survive  in  lizards."^ 

Lizards  are  very  various  in  size,  shape,  color,  and  habitat. 
Most  of  them  are  terrestrial,  some  burrow,  some  are  semi- 
aquatic,  and  still  others  are  arboreal.  They  are  generally  cov- 
ered with  horny  epidermal  plates  and  shed  their  skin  entire. 

The  shoulder  girdle  and  sternum  are  present.  The  "  flying 
dragons  "  of  the  Indo-Malayan  countries  have  "a  pair  of  wing- 


Fig.  200. —  Ildodd'inn  I  I  i()i-()iimi>,  lizard.  (From  Holder's  "Zoology," 
American  liook  Co.,  I'uhlislicrs  )  "The  blunt  tail  of  the  Gila  Monster  is 
actually  the  reservoir  for  the  storage  of  nourishing  fat." — Ditmars' 
"Reptiles  of  the  World." 

like  membranes  supported  l)y  five  or  six  elongated  posterior 
ribs,  which  they  use  as  a  parachute  or  fold  up  like  a  fan." 

Food. — Most  lizards  are  insectivorous,  eating  small  animals 
also,  but  some  are  herbivorous,  living  upon  buds,  V)lossoms,  and 
tender  leaves  of  plants. 

Special  Senses. — The  eyes  are  usually  provided  with  an 
upper  and  a  lower  movable  eyelid  and  with  a  transparent  nicti- 
tating membrane.  The  tympanic  membrane  is  situated  in  a 
slight  depression  behind  the  eye.  The  tongue  is  free  and  both 
jaws  are  armed  with  teeth.  The  mouth  is  not  distensible. 
1  Packard. 


LACERTILIA  245 

Multiplication. — The  egg-laying  lizards  deposit  their  eggs 
in  the  sand  or  soil,  except  the  Iguanidse,  which  lay  them  in  hol- 
low trees.  Many  lizards  are  viviparous.  The  male  is  larger 
and  more  brightly  colored  than  the  female. 

Lizards,  as  well  as  amphibians  and  snakes,  find  the  ocean  a 
barrier  to  their  progress,  but  lizard's  eggs  have  in  some  way  l)een 
carried  to  oceanic  islands. 

All  are  harmless  except  the  Gila  monster  (Fig.  200),  of  the 
Gila  River  region,  which  is  the  only  poisonous  lizard  known.  The 
specimen  in  our  laboratory  is  about  17  inches  long,  black,  and 
mottled  with  orange.  Its  only  sound  was  a  hiss,  which  it  gave 
when  disturbed. 


Fig.  201.- — Glass  snake  {Opheosau'rus  ventral' is).  The  tail  is  twice  the 
length  of  the  body,  and  breaks  off  at  the  slightest  blow.  When  broken  off 
it  grows  again.  (From  Baskett  and  Ditmars,  "The  Story  of  the  Amphib- 
ians and  Reptiles,"  D.  Appleton  and  Co.,  Publishers.) 

The  Skinks. — This  family  {Scin'cidoe)  is  represented  by  the  cosmopolitan 
blue-tailed  lizard  common  east  of  the  Rockies  as  far  north  as  northern 
Indiana,  and  by  the  ground  lizard  of  the  Southern  States. 

Cnemidoph'orus,  a  very  little  active  brown  lizard  streaked  with  yellow 
and  black,  is  found  from  Connecticut  to  Virginia  and  from  Wisconsin  to 
Mexico.  In  this  family  {Tc'idce)  there  are  over  one  hundred  species  dis- 
tributed throughout  South  and  Central  America  and  the  warmer  parts  of 
North  America. 

The  "glass  snake"  (Fig.  201),  our  representative  of  the  family  An'guidce, 
has  a  long  brittle  tail.     Its  brittleness  is  due  to  the  fact  that  not  only  are 


246 


BRANCH  CHORDATA 


the  caudal  vertebrae  loosely  joined  together,  but  each  vertebra  is  provided 
with  a  middle  cartilaginous  partition,  so  that  it  is  easily  separated.  The 
caudal  vertebra?  of  the  Geckones  and  of  most  Lacertae  break  in  the  same 
manner.  It  is  one  means  of  self  defense,  as  the  animal  escapes  with  only 
the  loss  of  its  tail.  The  popular  notion  of  the  pieces  being  collected  again 
is  without  foundation.  When  "  the  tail  is  broken  off,"  and  this  is  always 
at  this  cartilaginous  partition,  "  the  cells  of  the  remaining  half  reproduce  a 


'J 


Fig.  202. — An'olis  or  American  chameleon  {AnuUs  principalis).  Al- 
though the  general  color  of  the  animal  beneath  is  white,  the  upper  parts 
may  quickly  assume  hues  varying  from  a  vivid  emerald  green  to  a  dark 
iridescent  bronze  color.  (From  Baskett  and  Ditmars,  "  The  Story  of  the 
Amphibians  and  Reptiles,"  D.  Appleton  and  Co.,  Publishers.) 


new  tail."  This  new  tail,  says  Gadow,  is  only  a  "  sham  tail,"  since  it  does 
not  consist  of  a  series  of  vertebrae,  but  of  "  a  non-segmented  rod  or  tube  of 
fibrocartilage." 

This  lizard  cannot  climb,  and  does  not  like  the  water,  so  it  may  be  said 
to  bo  entir('l\'  terrestrial.  Its  food  consists  of  "  snails,  insects,  worms,  mice, 
small  lizards,  birds,  and  vipers."  It  shakes  its  prey  until  the  victim  is 
stunned,  th(>n  chews  and  swallows  it.  It  does  not  bite  when  caught,  but 
winds  about  the  wrist  and  emits  a  stinking  discharge.     It  hides  among  the 


LACKKTILIA  247 

leaves  and  in  tlic  sand  under  bushes.  This  species  lays  eggs,  though  some 
of  its  family  are  vi\  iparous.  It  hides  its  eggs  under  moss  and  leaves  and 
the  young  mature  very  slowly,  taking  several  years  to  reach  maturity. 

The  American  Chameleon  and  its  Relatives. — Our  very  interesting  lit- 
tle lizard  {An'oUn)  (Fig.  202)  of  Florida  and  the  Carolinas  is  commonly 
called  a  "chameleon,"  but  the  real  chameleon  is  a  native  of  Africa.  The 
"green  chameleon"  {Aiioliti)  has  the  power  of  suddenly  and  voluntarily 
changing  its  color  to  adapt  itself  to  its  eiu  irunmcnt.  Experiments  upon 
this  animal  in  our  laboratory  proved  that  it  changes  color  more  rapidly 
when  placed  upon  objects  with  natural  colors  than  it  does  upon  artificially 
colored  ones.  It  is  arboreal  and  insectivorous.  The  males  have  "  large 
gular  sacs  which  can  be  distended  by  the  hyoid  bones."  These  sacs  are 
white,  with  occasidna!  red  lines  and  spots,  but  when  inflated  they  become 
crimson.     The  Afialis  is  .">  or  6  inches  long. 

Another  member  of  this  family  is  our  little  Swift,  common  in  the  forests 
and  fence  corners  of  the  United  States  as  far  north  as  Michigan.  It  delights 
to  lie  basking  in  the  sun,  but  disappears  quickly  when  disturbed. 


Fig.  203. — The  "  homed  toad"  {Phrynoso'maUainvUki} .  The  spiny  cov- 
ering repels  many  enemies.  (From  Jordan  and  Kellogg,  "  Animal  Life/' 
D.  Appleton  and  Co.,  Publishers.) 

Another  member  is  the  very  interesting  little  lizard  called  the  "horned 
toad"!  (Fig.  203),  Phrynoso'nia,  found  in  the  dry  regions  (jf  the  Southwest- 
ern States.  The  body  is  oval  in  form,  rather  flat  and  broad,  with  a  short 
conical  tail.  It  is  covered  with  irregularly  shaped  keeled  or  spiny  scales,  the 
head  Ixnng  "bordered  ))()steri(ii-ly  with  osseous  spines."  The  small  eyes  are 
each  i)rot('cte(l  by  a  ridge  running  l)ai'kwar(I  above  them.  The  ventral  side 
of  the  author's  |)et  "iiorned  toad,"  a  specimen  from  southeast  Kansas,  is 
yellowish  in  color,  with  a  number  of  brown  spots  dotted  over  it.  The  scales 
are  small  and  regular.  The  general  color  of  the  animal,  dorsally,  is  grayish 
or  yellowish  brown,  atfoiding,  togetliei-  witli  its  irregul.ir  and  roughened  "sur- 
face, an  excellent  protect  i\c  jesemhlaiice  to  tJie  sand  in  thi"  desert  regions, 
in  which  it  likes  to  sink  until  the  spines  of  the  Inad  alone  stick  out.  Thus 
some  species,  at  any  rate,  lie  concealed  through  tlie  night  and  on  cloudy 
days.  They  are  livehest  in  the  middle  of  the  day  and  delight  in  the  hot  suii. 
When  alarmed  they  shut  their  eyes  and  lie  flat  on  the  sand.  Their  food 
is  insects,  which  they  catch  as  toads  do  with  their  tongues,  which  are  smooth, 
short,  and  scarcely  at  all  notched,  and  can  be  thrust  out  a  short  distance 

1  Better,  "Horned  Lizard."    It  is  not  a  toad  (Amphibian,  it  is  a  re])tile). 


248  BRANCH    CHORDATA 

only,  perhaps  not  over  i  inch.  "  Horned  toads  "  will  endure  long  fasts. 
They  hibernate  in  winter.  All  species  are  viviparous  and  the  young  at 
one  litter  number  seven  or  eight. 

Another  Iguana  {tuberculata) ,  of  South  and  Central  America  and  the 
West  Indies,  is  sometimes  5  or  6  feet  long  and  weighs  nearly  30  pounds. 
It  spends  much  of  its  time  in  trees,  but  when  alarmed  plunges  into  the 
water  below  it.  It  lays  about  two  dozen  eggs  in  a  hole  in  the  side  of  the 
bank.     The  flesh  of  these  animals  is  much  prized  for  food  by  the  natives. 

The  Monitors. — The  one  genus  ( Var'anus)  of  this  family  ( Varan' ida) 
consists  of  about  thirty  species.  They  are  found  in  Africa,  but  not  in 
Madagascar,  in  Australia,  and  in  Southern  Asia.  They  have  long  forked 
extensible  tongues.  They  are  large,  attaining  the  length  of  4  or  5,  or  even 
6  feet.  Some  are  found  in  desert  or  dry  regions,  while  others  are  semi- 
aquatic.  The  natives  of  some  regions  use  the  flesh  of  the  monitors  for 
food.  The  monitors  are  rapacious,  devouring  any  animals  which  they 
can  get.  "The  Monitor  {Var'anus  nilot'icus)  is  a  great  water-lizard  that 
lives  in  the  Nile.  It  is  the  principal  enemy  of  the  crocodile.  When  full 
grown  it  reaches  a  length  of  6  feet  or  more." — Kellogg. 

Library  Work. — See  Gadow  or  other  large  works  on  reptiles 
for  an  extended  description  of  Lacertilia  of  the  tropical  regions. 
The  "  Flying  Dragon  "  and  other  interesting  forms  are  well 
worth  your  study.  Baskett  and  Ditmar's  "  Story  of  Amphib- 
ians and  Reptiles  "  relates  many  interesting  facts  in  a  simple, 
yet  instructive  manner,  also,  Hornaday's  "  American  Natural 
History."  Do  not  fail  to  read  the  larger  works.  Get  beyond 
mere  text-book  study  of  these  wonderful  forms  in  this  and  other 
lands.     Broaden  your  own  horizon. 

ORDER  IV.      CHELONIA 

Turtles  vary  in  size  from  a  few  inches  in  length  to  6  or  more 
feet  in  some  marine  forms.  The  turtles  of  to-day  are  small  as 
compared  with  some  extinct  forms.  They  vary  in  weight  from 
a  few  ounces  to  over  1000  pounds.  There  are  marine,  fresh- 
water, and  land  forms,  while  the  "  gophers  "  of  the  South  bur- 
row in  the  ground. 

Skeleton. — Turtles  are  easily  recognized  by  their  shell  or 
exoskeleton.  The  dorsal  portion  of  the  shell  is  called  the  cara- 
pace, and  the  ventral  portion  the  plastron.  The  covering  of  this 
shell  consists  of  horny  epidermal  plates.  These  are  thin,  and 
when  pulled  off  reveal  the  bony  shields  beneath. 

The  bony  carapace  (Figs.  204,  205)  is  composed  of  the  spines  of 
the  dorsal  vertebra?,  flattened,  the  ribs  broadened  out  and  joined 
to  each  other  by  sutures,  also  to  the  outer  marginal  row  of 


CHELONIA 


249 


Fig.  204. — Bony  carapace  of  turtle  with  epiflermal  plates  removed  to  reveal 
bony  shield  with  portion  missing.     Dorsal  view. 


Fig.  205. — Bony  carapace  of  turtle.    Notice  how  the  ribs  are  broadened  and 
joined  by  sutures.     Ventral  view. 


250  BRA^X'H    CHORD  ATA 

dermal  bones,  all  fused  into  one  bony  carapace  which  is  covered 
by  epidermal  plates.  The  plastron  consists  of  epidermal  plates 
underlaid  with  bony,  shields.  The  head,  limbs,  and  tail  may  be 
more  or  less  withdrawn  under  the  carapace  for  protection;  in 
some  forms  so  completely  that  there  is  no  part  of  the  turtle 
visible  outside  of  the  shell. 

They  have  four  short,  strong,  clawed,  pentadactyle  limbs,  or, 
in  the  case  of  some  marine  forms,  flippers.  The  marine  paddle- 
limbed  forms  are  usually  designated  as  turtles,  and  those  with 
walking  limbs  as  tortoises. 

The  hones  of  the  head  are  firmly  united.  The  jaws  are 
toothless,  but  are  inclosed  in  sharp  horny  beaks,  with  which 
they  seize  and  crush  their  prey  and  then  swallow  it  whole. 
The  pectoral   arch   is  a   "triradiate  structure,  of  which  the 


Fig.  206. — Skeleton  of  snapping-turtle  with  portion  of  carapace  sawed  oflf 
to  show  interior.     Cleaned  and  mounted  by  students ;   (much  reduced.) 

most  ventral  and  posterior  ray  ending  in  a  free  extremity  is 
the  coracoid,  while  the  other  two  are  the  procoracoid  and  the 
scapula  with  the  suprascapula,  which  are  fused  at  their  glenoid 
ends."^  The  pelvis  is  strong,  consisting  on  each  side  of  the 
pubis,  the  ischium,  and  the  ilium.  These  meet  at  the  articular 
surface  of  the  hind  limb.  The  vertebrae  are  few  as  compared 
with  those  of  the  snake.  Those  of  the  neck  fit  into  one  another 
with  ball-and-socket-joint.  There  is  no  trace  of  a  sternum  or  of 
sternal  ribs. 

Digestive  System. — The  tongue  is  usually  soft  and  wide  and 
not  extensible.  The  esophagus  is  covered  with  "  conical  pro- 
jections pointing  toward  the  stomach."     There  is  no  cecum. 

Food. — Some  species  are  carnivorous,  some  are  herl^ivorous, 

1  Parker  and  Haswell,  vol.  ii,  p.  329. 


CHELONIA  251 

while  others  are  omnivorous.  Predacious  species  probably 
lie  in  wait  for  their  prey. 

The  respiration  is  unique.  The  large  spongy  lungs  reach  to 
the  pelvis.  In  breathing  the  neck  and  limbs  act  like  pistons  in 
being  drawn  in  and  out.  The  throat  is  alternately  inflated  and 
emptied  by  the  hyoidean  apparatus  when  the  neck  is  stretched 
out,  thus  the  air  is  swallowed  or  pumped  into  the  lungs.  Since 
the  lungs  are  so  roomy  and  the  animals  poikilothermal,  most 
turtles  can  live  for  a  long  time  without  breathing,  sometimes 
remaining  under  water  for  hours  or  even  days. 

Special  Senses. — Their  eyes,  though  comparatively  small, 
are  their  most  highly  developed  sense  organ.  They  are  situ- 
ated far  forward  on  the  head  and  protected  by  two  lids  and  a 
nictitating  membrane.  The  nostrils  are  terminal;  thus  by  ex- 
posing a  minimum  portion  of  the  head  above  water  they  are 
able  to  breathe  and  see  what  is  going  on  about  them,  compara- 
tively free  from  danger.  The  sense  of  smell  is  well  developed, 
many  species  showing  a  choice  of  certain  kinds  of  food  which 
they  distinguish  by  smell.  The  sense  of  hearing  is  not  well 
developed.  That  they  distinguish  sounds  is  evident  from 
their  voice,  which  Gadow  declares  is  very  tiny  and  piping  during 
the  pairing  season.  Some  species,  at  least,  snap  their  jaws 
together  when  angry,  and  when  the  head  and  limbs  are  with- 
drawn they  make  a  hissing  sound.  Holder  says  the  male 
"  elephant  turtle  "  of  the  Galapagos  Islands  "  utters  a  hoarse 
croak  or  bellow  during  the  breeding  season."  They  are  fright- 
ened by  noise.  The  tympanic  membrane  in  most  water  forms 
is  thin  and  quite  exposed.  In  land  tortoises  it  is  often  thick  and 
covered  with  the  skin.  Turtles,  contrary  to  the  notion  of  small 
boys,  are  very  sensitive  to  the  touch,  both  upon  the  shell  and 
upon  the  soft  parts. 

Multiplication. — Turtles  lay  their  eggs  at  night  in  the  sand, 
cover  them  carefully,  and  leave  them  for  the  heat  of  the  sun- 
warmed  sand  to  hatch. 

The  young  are  like  the  adult  in  general,  but  differ  somewhat 
in  color. 

Enemies  and  Defense. — They  are  preyed  upon  by  carnivo- 
rous birds,  fishes,  alligators,  and  by  men.  They  defend  them- 
selves by  closing  up  their  shell,  as  the  box  turtle;  by  snapping 


252  BRANCH    CHORDATA 

and  scratching,  as  the  snapping  turtle;  by  swimming  away  or 
by  hiding  in  the  mud,  and  thus  escaping  by  the  protective 
resemblance.     They  hibernate  in  winter  in  this  latitude. 

The  leathery  shelled  sea-turtle  {Sphar'gis  coriacea)  is  the  largest  of  all 
recent  turtles.  It  is  from  6  to  8  feet  long,  and  of  a  dark  brown  color,  and 
may  weigh  500  pounds  or  more.  It  is  widely  distributed  in  the  tropical 
seas,  but  it  is  abundant  nowhere.  The  dorsal  and  ventral  portions  of  the 
weak  bony  shell  are  continuous.  It  is  buried  under  a  layer  of  fat  which 
yields  "  about  a  pint  of  oil  to  each  square  foot.''^  The  sea-turtles  have 
long  flat  triangular  flippers  without  toes  or  claws.  The  front  flippers  are 
long.      Its  flesh  is  Tiot  cdiblo. 

Hard-shelled  Sea-turtles  (Chelon'idce) . — In  this  group  is  found  the  green 
turtle,  one  of  the  most  widely  distributed  of  the  Atlantic  turtles.  It  is 
found  from  Long  Island  to  Cuba  and  south  to  Brazil  and  also  in  the 
Indian  Ocean.  Its  flesh  is  prized  for  food.  It  varies  in  weight  from  50  to 
500  pounds. 

The  tortoise-shell  turtle,  from  which  is  obtained  the  valuable  tortoise 
shell,  has  its  upper  jaw  terminated  in  a  strongly  hooked  beak.  Until  the 
animal  is  very  old  the  shields  overlap  one  another  from  before  backward. 
The  scales  are  clear  yellowish  horn  beautifully  mottled  with  black  and 
brown.  These  turtles  do  not  reach  the  size  of  the  green  turtle;  the  largest 
one  on  record,  says  Gadow,  is  34  inches  long.  They  range  over  all  the 
tropical  and  subtropical  seas,  being  found  occasionally  around  the  Bahama 
Islands. 

The  soft-shelled  turtles  (Trionych'idop)  are  of  wide  distribution  both  in 
time  and  space.  The  shell  is  very  flat  and  almost  circular.  It  is  imper- 
fectly ossified  both  above  and  below,  and  terminates  at  the  edges  in  thin 
plates  of  leathery  skin.  When  properly  cooked  the  shell  is  tasty .^  These 
turtles  are  brown,  mottled  with  black  above  and  clear  white  below,  and 
weigh  from  20  to  80  pounds. 

The  Snapping  Terrapins  {Chelijd'ridce). — This  family  includes  the  alli- 
gator snapper,  the  largest  North  American  terrapin  of  the  Gulf  States,  and 
our  common  "  snapping  turtle  "  found  everywhere  in  fresh-water  ponds 
and  streams.  The  snapping  terrapin  has  very  powerful  strongly  hooked 
jaws,  a  long  tail  with  a  crest  of  bony  compressed  tubercles,  and  a  small 
cross-shaped  plastron.  It  seldom  leaves  the  water.  It  is  carnivorous,  very 
voracious,  and  savage.     It  is  destTuctivc  to  fishes  and  water  birds. 

The  Smooth-shelled  Terrapins  {Emyd'id(p). — The  diamond-back  terra- 
pin is  found  (or  was  until  so  much  hunted  for  food)  in  salt  marshes  from 
New  York  to  Teaxs.  It  varies  in  color  from  greenish  to  dark  oli\(>  or  black 
(rarely).  It  is  small,  one  weighing  a  pound  is  consid(>red  large.  It  is 
regarded  as  the  choicest  variety  for  a  terrapin  stew.  It  is  said  tliat  there 
are  several  "terrapin  farms"  in  the  South  in  which  this  turtle  is  being 
reared  for  the  market.  Unless  some  such  provision  is  made  \\\vy  will  soon 
be  exterminated. 

The  painted  terrapin  {Chry'semys  pic'ta)  is  common  in-most  regions  east 
of  the  Missis.sippi.  The  shell  is  much  depressed.  The  plates  of  the  cara- 
pace in  Chrysemys  picla  are  greenish  black  edged  with  yellow,  those  about 

^  Hornaday,  p.  331. 
2  Ibid. 


CROCODILIA  253 

the  margin  being  conspicuously  marked  with  red.  The  plastron  is  yellow, 
blotched  with  brown.  There  are  markings  of  yellow  and  red  upon  the 
sides,  neck,  limbs,  and  tail,  a  pair  of  bright  yellow  patches  behind  the  eyes, 
and  a  smaller  pair  on  the  back  of  the  head.  The  toes  are  strong  and  broadly 
webbed.  They  are  especially  fond  of  insects  and  worms.  They  are  very 
shy  and  active.     Chryscmys  marginata  is  a  western  form. 

The  common  box-turtle  {Cistu'do),  a  terrestrial  member  of  this  group,  is 
built  for  life  on  land.  Its  carapace  is  high  and  it  can  withdraw  its  head, 
legs,  and  tail  within  it.  Across  the  center  of  the  plastron  is  a  double 
hinge,  so  that  when  disturbed  it  completely  shuts  itself  in  the  box,  and 
nothing  short  of  injuring  the  shell  can  harm  it.  One  was  once  subjected 
to  a  strong  dose  of  chloroform  in  our  tight-covered  "  killing  jar  "  for  two 
hours  with  little  or  no  effect,  so  tightly  was  it  shut  up  in  its  box.  It  is  surely 
a  good  illustration  of  special  adaptation  to  environment.  Since  it  cannot 
run,  like  the  rabbit,  nor  swim,  like  its  relatives  of  the  streams,  it  closes  up 
its  house  and  remains  motionless.  It  is  found  from  New  York  to  Missouri 
and  southward. 

The  musk  terrapin  (Aromoch'dys  odora'tus),  a  representative  of  the  family 
Kinostcrnidw,  is  a  small  fresh-water  specimen  which  has  a  strong,  musky 
characteristic  odor.  Its  food  consists  of  aquatic  insects,  small  fishes,  and 
worms. 

The  Land  Tortoises  (Testitdin'idce) . — The  giant  tortoise,  which  inhabits 
the  Galapagos  Islands  and  two  islands  of  the  Indian  Ocean,  is  the  only  sur- 
vivor of  a  race  of  giant  tortoises  of  the  Reptilian  Age.  A  specimen  once 
in  the  New  York  Zoological  Garden  weighed  310  pounds,  and  was  estimated 
to  be  four  hundred  years  old. 

Almost  every  island  of  the  Galapagos  group  has  had  or  has 
its  own  peculiar  form  of  tortoise.  How  they  got  to  these  islands 
or  where  they  came  from  it  is  impossible  to  say  definitely. 
They  could  not  have  migrated,  since  land  tortoises  are  easily 
drowned,  and  anyway,  "  there  are  now  none  of  their  kind  on  the 
continents  of  Asia,  Africa,  or  South  America."^  So  it  is  as- 
sumed that  they  are  descendants  of  tortoises  once  populating 
the  land  which,  except  these  islands,  now  lies  below  the  Indian 
Ocean. 

Our  native  species  of  this  family  is  the  Gopher  tortoise,  found 
in  the  pine  barrens  of  the  Southern  States. 

ORDER   V.      CROCODILIA 

Crocodiles  and  alligators  are  the  largest  of  living  reptiles, 
some  of  the  largest  crocodiles  attaining  a  length  of  30  feet. 
They  are  covered  with  horny  plates  or  scales. 

The  head  is  remarkable  for  its  powerful  jaws,  whose  enor- 
mous gape  enables  the  animal  to  seize  and  crush  its  prey. 
The  eyes,  nostrils,  and  ears  are  on  top  of  the  head.  While 
1  Gadow. 


254  BRANCH    CHORDATA 

exposing  only  a  small  part  of  its  body,  it  can  see  and  hear  well 
the  approach  of  an  enemy.  "  Crocodiles  are  the  only  reptiles 
whose  nostrils  open  in  the  throat  behind  the  palate  instead  of 
directly  into  the  mouth  cavity.  This  enables  the  crocodile  to 
drown  its  victim  without  drowning  itself,  for  by  keeping  its 
snout  above  water  it  can  breathe  with  its  mouth  wide  open."^ 
When  under  water  the  nostrils  are  closed  by  a  valve. 

Limbs  and  Tail. — Their  four  limbs  are  stout,  short,  and 
powerful.  The  tail  is  strong  and  compressed.  It  aids  the 
animal  in  locomotion,  in  self-defense,  and  in  knocking  its  prey 
off  the  bank  into  the  water,  where  it  is  seized  and  held  under 
water  until  strangled  to  death. 

Habits. — They  are  aquatic  and  nocturnal  in  activity,  feed- 
ing at  night  upon  fishes,  birds,  mammals,  and  whatever  they  can 
capture.  Hornaday  describes  how  an  alligator  dismembered 
its  victim.  It  seized  the  prey  by  one  leg,  whirled  itself  round  and 
round  till  the  leg  was  twisted  off.  He  saw  another  shake  a  com- 
panion until  the  skin  of  its  back  was  torn  in  two. 

They  hibernate  in  temperate  regions,  and  estivate  or  migrate 
in  tropical  regions  when  drought  overtakes  them. 

The  Florida  crocodile  digs  burrows  in  the  sandy  banks.  The 
entrances  are  wholly  or  partly  under  water.  At  the  farther  end 
the  l)urrow  is  wide  enough  for  the  crocodile  to  turn  round  in. 

They  lay  their  large  white  eggs  in  the  sand  away  from  the 
water,  or  build  rude  nests  or  mounds  in  which  they  deposit  their 
eggs  in  layers  and  watch  and  defend  them  until  the  young  are 
hatched.  Ditmars  says,  "The  alligator  has  entire  head  broad, 
bluntly  rounded  at  snout.  The  crocodile  has  head  triangular; 
becoming  very  narrow  toward  snout." 

The  ga'vial  of  India  (Fig.  207)  is  long,  and  slender  snouted.  The  animal 
may  reach  a  length  of  20  feet,  but  is  harmless  to  man,  being  a  fish-eater. 

Alligators.— The  male  alUgator  may  reach  a  length  of  12  feet  and  the 
female  that  of  8.  The  male  has  a  heavier  and  more  powerful  head  and  is 
the  more  brilliantly  colored  during  the  breeding  season.  The  large  nest  is 
built  by  the  female  on  the  bank  of  a  stream  or  pool.  The  young  are  active 
and  shift  for  themselves.  The  aUigator  finds  its  northern  limit  in  North 
Carolina,  about  3.5°  North  Latitude.  From  here  south  they  abound  near 
the  mouths  of  creeks  and  rivers  as  far  south  as  the  Rio  Grande  _  They 
ascend  the  Mississippi  to  33°  50"  North  Latitude,  or  to  the  mouth  of  the 
Red  River.  .  .  r     x  i  r 

There  is  a  small  species  of  alligator  in  China.  It  is  about  b  leet  long,  ot 
a  greenish  black  color  dotted  with  yellow. 

1  Dodge,  p.  476. 


^^^ 


r 


Fig.  207. — Gavial  {Gavia'lis  gange'tica).  (From  Basket t  and  Ditmars, 
"  The  Story  of  the  Amphibians  and  Reptiles,"  D.  Appleton  and  Co., 
Pubhshers.) 


Fig.  208.— Crocodiles.     (From  Baskett  and  Ditmars,  "  The  Story  of  the 
Amphibians  and  Reptiles,"  D.  Appleton  and  Co.,  Publishers.) 

The  caiman,  of  Central  and  South  America  and  the  West  Indies,  is  some- 
thing like  our  alligators  and  may  reach  a  length  of  from  6  to  20  feet. 

The  crocodile  (Fig.  208)  of  the  Nile  and  Madagascar  and  Asia  is  the 
largest  of  the  order,  sometimes  reaching  a  length  of  over  20  feet.  Hornaday 
says  four  species  of  crocodiles  are  found  in  America,  and  that  only  three  of 
the  nineteen  species  of  crocodiles  are  dangerous  to  man,  the  most  dangerous 


256  BRANCH    CHORDATA 

of  these  being  the  "  salt-water  crocodile  "  of  the  Malay  Peninsula.     The 
American  crocodile  and  the  alligator  are  not  dangerous  to  man. 

"  The  Florida  crocodile  is  the  only  crocodile  which  inhabits  a  country 
that  is  visited  by  killing  frosts."'  It  is  most  abundant  in  low  wet  lands  and 
shallow  water,  where  the  mainland  sinks  into  the  gulf.  There  is  a  Cuban 
crocodile  and  two  South  American  species. 

Distribution  of  Reptiles. — The  animals  of  this  class  are 
generally  tropical  and  subtropical.  Snakes  are  said  to  extend 
farther  north  in  America  than  do  lizards.  In  Europe  snakes  are 
not  found  north  of  60°,  while  lizards  are  sometimes  found  farther 
north  or  at  an  elevation  of  ten  thousand  feet. 

Lizards  are  the  most  numerous  of  reptiles  at  the  present  time, 
and  are  found  in  all  except  the  circumpolar  regions. 

Chelonia  are  also  widely  distributed  in  the  tropical  and  tem- 
perate regions. 

The  alligators  occur  only  in  North  America  and  in  China,  and 
the  Caimans  are  found  only  in  Central  and  South  America. 
Crocodiles  are  distributed  over  Africa,  southern  Asia,  northern 
Australia,  and  tropical  America,  there  being  one  species  in 
Florida. 

True  reptiles  are  known  to  have  existed  in  the  Permian  Pe- 
riod. Indeed,  there  was  such  a  "variegated  reptilian  fauna"  that 
it  is  believed  their  ancestors  must  have  lived  in  the  Carboniferous 
Period.  One  of  the  Permian  orders  ( Theromor'pha)  exhibits  cer- 
tain strong  points  of  resemblance  to  the  earliest  amphibians  and 
other  jDoints  of  resemblance  to  the  lower  animals.  They  have 
been  found  in  rocks  of  the  Permian  and  Triassic  Periods,  but  in 
none  of  the  more  recent  formations.  These  fossils  have  been 
found  in  Texas,  South  America,  Europe,  Africa,  and  India. 

Lizard-like  forms  {Sauroptery' gia)  existed  in  the  Cretaceous 
and  Triassic  and  possibly  in  the  Permian  periods.  They  varied 
from  small  forms  up  to  those  of  40  feet  in  length.  A  fish-like 
form  (Ichthyoptery'gia),  varying  from  30  to  40  feet  in  length,  ex- 
isted from  the  upper  Triassic  to  the  upper  Cretaceous  periods. 
In  the  Triassic  were  also  forms  allied  to  the  crocodile. 

One  of  the  most  characteristic  of  the  Mesozoic  orders  of 
reptiles  was  the  Dinosauria,  many  of  which  existed  in  the  Triassic 
Period.     Some   were  herbivorous,    others  carnivorous.     Some 

1  Hornaday. 


CROCODILIA  257 

walked  on  all  fours,  others  occasionally  or  habitually  walked 
upright,  after  the  manner  of  l)irds,  with  which  they  had  many 
structural  features  in  common.  Their  size  was  so  great  that  the 
footprints  measured  from  14  to  18  inches.  The  length  was 
sometimes  60  to  70  feet  and  the  height  nearly  20  feet. 

The  earliest  turtles  were  found  in  the  Triassic  of  Europe. 
True  lizards  appeared  and  turtles  abounded  in  the  Jurassic. 
The  Pterosau'ria  appeared  in  the  Jurassic.  They  had  toothed 
jaws  and  were  winged  like  a  bat.  The  spread  of  wings  did  not 
exceed  3  feet.  In  the  Cretaceous  Period  the  spread  of  wings  was 
20  feet.  Gigantic  carnivorous  marine  lizards  swarmed  on  the 
Atlantic  and  Gulf  coasts  and  in  the  interior  seas  of  that  time. 

In  the  tertiary  period  reptilian  life  shows  a  great  change,  the 
animals  being  neither  so  large  nor  so  varied. 

All  the  fossil  snakes,  except  one  found  in  the  cretaceous,  have 
been  found  in  the  tertiary  period.^ 

It  is  plain  to  be  seen  why  the  Mesozoic  Era  is  called  the  "age 
of  reptiles,"  and  how  closely  related  the  reptiles  are  to  both 
amphibians  and  birds.  They  differ  from  amphibians  in  having 
bodies  covered  with  scales,  in  having  but  one  occipital  condyle, 
in  having  the  embryonic  membranes,  the  amnion  and  allantois; 
in  Crocodilia,  in  having  a  four-chambered  heart;  in  never  having 
gills,  and  in  never  having  a  tadpole  stage.  They  differ  from  birds 
in  having  scales,  but  never  feathers,  and  in  the  circulation  (being 
poikilothermal) .  If  we  include  the  extinct  forms,  there  will  be 
found  many  points  of  similarity  between  reptiles  and  birds. 
Hence  it  is  believed  that  amphibians,  reptiles,  and  birds  h^ve  a 
common  ancestry. 

Economic  Importance. — As  has  been  mentioned,  many  rep- 
tiles are  used  for  food.  The  skins  of  rattlesnakes  and  boas  are 
made  into  bags,  cases,  boots,  saddle  cloth,  etc.  The  oil  of  the 
rattlesnake  and  boas  is  valuable,  and  that  of  the  copperhead  is 
used  in  medicine.  The  scales  of  the  tortoise-shell  turtle  are 
valued  for  combs  and  ornaments,  and  the  oil  from  its  eggs  is 
used  in  dressing  leather.  From  alligators  we  get  valuable 
leather,  oil,  and  musk.  The  teeth,  flesh,  hide,  and  oil  of  croco- 
diles are  valued. 

Most  of  our  common  forms  are  not  dangerous  to  man,  and, 
*  Parker  and  Haswell. 
17 


258  BRANCH    CHORDATA 

any  way,  will  not  attack  him  if  unmolested.  A  few  forms  of 
snakes  and  crocodiles  are  dangerous  to  man. 

Important  Biologic  Facts. — The  embryonic  membranes,  the 
amnion  and  the  allantois,  first  appear  in  this  class.  Respiration 
is  by  lungs.  True  nostrils  appear.  The  heart  is  four  cham- 
bered in  Crocodilia. 

Classification. — 

Order.  Examples. 

I.  Rhynchocepha'lia.  Sphenodon  punctatum. 

II.  Ophid'ia.  Snakes. 

III.  Lacertil'ia.  Lizards. 

IV.  Chelo'nia.  Turtles. 

V.  CrScodil'ia.  Crocodiles,  alligators. 

CLASS  V.     AVES 

"  I  have  considered  the  birds, 
And  I  find  their  Hfe  good. 
And  better,  the  better  understood." 

(McDonald.) 

In  existing  forms,  birds  are  feathered  chordates  having  no 
teeth,  but  from  paleontology  we  learn  that  some  of  the  fossil 
birds  (Figs.  209-212),  as  the  Archceop'teryx  (Fig.  212),  of  the 
Jurassic  Period,  had  teeth  and  a  long  vertebrated  tail. 

Birds  have  several  characteristics  in  common  with  reptiles, 
among  which  are  the  large  eggs,  the  lack  of  a  complete  dia- 
phragm, the  quadrate  bone  connecting  the  lower  jaw  with  the 
skull,  and  the  single  occipital  condyle.  It  is  believed  that  in  the 
early  stages  of  their  development  birds  floated  in  the  air  by 
means  of  a  patagium,  or  wing  membrane,  and  that  even  "feath- 
ers were  used  at  first  as  a  means  of  sailing  down"  after  having 
crawled  up  to  some  height  by  the  use  of  claws  on  the  "fingers," 
vestiges  of  which  are  yet  shown  by  many  birds,  such  as  the 
turkey,  the  vulture,  certain  ostriches,  swans,  thrushes,  and 
young  gallinules,  which  have  claws  variously  located  on  the 
wing  tips. 

Covering. — The  lower  part  of  the  legs  is  covered  with  hard, 
reptile-like  scales,  or  epidermal  shields,  for  protection.  The 
beak  and  claws  are  also  horny  epidermal  structures. 


AVES 


259 


The  skin  of  a  Ijinl  is  thin  and  the  body  is  not  uniformly 
covered  with  feathers  (Fig.  213).  There  are  many  bare  spots, 
as  may  be  readily  seen  by  turning  back  the  feathers  on  the  neck 
or  breast.  The  bare  spaces,  apteria,  are  concealed  by  the  over- 
lapping feathers.  Note  where  the  feathers  grow.  These  spaces 
are  called  pterylce,  from  two  Greek  words  meaning  "feather 
forest." 

Feathers  are  homologous  with  scales,  as  "the  feather  may  be 
regarded  as  a  cornified  outgrowth  from  the  skin,  which  has  arisen 


Fig. 


209. — Ichthyor'nis   victor, 
(Restored  by  Marsh.) 


Xi. 


Fig.  210. —  Hesperor'nis  regal' is,  X  xV- 
(Restored  by  Marsh.) 


on  a  papilla  of  the  derma."^  A  large  wing  feather,  for  example, 
is  made  up  of  the  central  stalk  and  the  expanded  part,  or  vane. 
The  hollow  portion  of  the  stalk  nearest  the  body  is  the  quill, 
and  the  remaining  part,  the  rachis  or  shaft.  The  vane  is  com- 
posed of  side  branches  or  barbs,  the  barl)s  of  side  branchlets  or 
l)arbules,  which  are  provided  with  hooks.  The  hooks  of  one 
barbule  interlock  with  those  of  the  next  and  thus  hold  the  parts 
of  the  vane  together.  In  down  feathers  the  hooks  are  lacking. 
1  Hertwig. 


260  BRANCH    CHORDATA 

The  large  feathers  on  the  wing  and  tail  are  called  quills;  the 
similar  but  smaller  ones  on  the  body,  the  contour  or  outline 
feathers;  those  without  barbs,  down;  and  the  hair-like  ones,  the 
filoplumes  or  pin-feathers.     These  different  kinds  have  various 


Fig.  211. — Dinor'nis  giganteus,  X  jg.     (From  a  photograph  of  a  skeleton  in 
Christchurch  Museum,  New  Zealand.) 

uses.  Can  the  student  see  the  advantage  to  the  bird  of  each 
kind  of  feather?  What  use  does  man  make  of  the  different  kinds 
of  feathers? 

''Since  the  feathers  are  not  only  for  protection,  but  give  to 
most  birds  the  power  of  i)rolonged  flight,  they  predict  a  special 


AVES 


261 


mode  of  life.  The  character  of  the  skeleton,  the  respiratory 
organs,  and,  in  part,  the  sense  organs  and  brain  are  connected 
with  the  powers  of  flight."' 

Variation  in  Plumage. — The  changing  of  the  feathers  and  the 
colors  of  birds  is  very  little  understood.  The  nestling  plumage 
may  be  so  meager  that  we  speak  of  the  young  as  naked,  but  the 
precocial  forms,  as  the  grouse,  snipes,  and  ducks,  have  a  thick 
covering  of  down.     This  is  followed  by  what  is  known  as  the 


Fig.  212.— A,  Archneopteryx  mncrura,  rostonnl  (Fowler).     B,  Section  of  the 
tail  (after  Owen)       (Romanes). 


first  piumage,  which  appears  more  quickly  upon  the  naked  than 
upon  the  down-covered  young  and  which  may  be  unlike  that 
of  either  parent.  In  most  land  birds  this  is  soon  followed  l:)y 
the  immature  plumage  to  be  worn  during  the  winter.  This 
plumage  may  ])e  like  that  of  the  adult  parent  of  the  same  sex, 
or  it  may  be  that  both  immature  males  and  females  may  resemble 
the  adult  female,  or  they  may  be  unlike  either  parent.     In  the 

'  Hertwig,  p.  604. 


262 


BRANCH    CHORDATA 


first,  second,  or  even  the  third  spring  the  plumage  becomes  Uke 
that  of  the  adult. 

The  time  of  molting  varies  not  only  among  different  species, 
but  often  among  different  individuals  of  the  same  species,  ac- 
cording to  sex,  age,  and  physical  conditions.  All  birds  molt  after 
the  nesting  season.  Some  birds  lose  a  few  of  the  body  feathers 
in  the  next  spring  before  the  nesting  season,  while  many  lose  the 
body  feathers,  but  not  those  of  the  wing  and  tail.    Some  change 


Fig.  213.— Pterylse  and  apteria  of  Gallus  bankiva  (Nitzsch):    a,  Ventral 
side;  b,  dorsal  side. 


color  by  wearing  off  the  fringes  of  the  feather  tips,  and  others 
at  this  season  are  adorned  with  special  nuptial  plumes,^  such  as 
the  aigrette  of  the  heron,  for  which  these  birds  have  been  so 
slaughtered. 

There  are  no  periodic  molts  of  the  skin,  as  in  reptiles,  but  the 
horny  layer  of  the  integument  undergoes  a  constant  renewal,  as 
in  mammals.     Some  penguins,  it  is  said,  "exhibit  the  old  rep- 

1  Chapman,  "  Bird  Life,"  p.  38. 


AVES 


263 


tilian  habit  of  shedding  theirs  in  great  flakes,  with  feathers 
attached."^ 

General  Structure.— The  skull  (Fig.  2U)  is  thin;  the  bill  or 
horny  beak  varies  much  according  to  its  use;  and  there  is,  as  in 
reptiles,  only  one  occipital  condyle.  The  neck  is  long  and  flex- 
ible. In  different  kinds  of  birds,  the  number  of  neck  vertebrae 
varies  from  eight  to  twenty-four. 

The  wings  are  adapted  for  flight  in  our  birds.  While  the 
ostrich  cannot  fly,  its  rudimentary  wings  are  compensated  for 
by  its  very  strong  legs,  which  are  adapted  for  rapid  running. 
No  other  animal  has  wings  of  the  same  structure  as  a  bird's. 
The  characteristic  structure  of  the  wing-bones  is  the  hand.  It 
is  comparable  with  the  human  hand. 


Fig.  214. — Skull  of  parrot:  22,  Premaxillary  bone  ensheathed  in  horn; 
15,  nasal  bones;  v,  mandible,  the  end  sheathed  with  horn;  I,  malosquamosal 
zygomatic  style  or  maxillojugal  bar;  g,  postfrontal  bone;  o,  lacrimal 
bone;  n,  nostril,  showing  also  the  articulation  of  the  nasopremaxillary 
bone;  e,  quadrate  bone;  m,  orbit;  1,  occipital  bone.     (After  Owen.) 


The  legs  and  feet  (Fig.  215)  of  birds  are  adapted  for  running, 
scratching,  swimming,  or  perching.  Note  the  position  of  the 
thigh  (femur)  on  the  side  of  a  bird.  Do  you  see  any  advantage 
of  such  a  position?  Distally  the  femur  or  thigh  is  joined  to  the 
tibiotarsus  and  the  fibula,  which  is  found  partially  united  with  the 
tibiotarsus.  The  proximal  row  of  tarsal  bones  unites  with  the 
distal  end  of  the  tibia,  hence  the  name  tibiotarsus  or  ''drum- 
stick" in  the  chicken.  The  distal  row  of  tarsal  bones  unites  with 
the  metatarsal  bones  to  form  the  tarsometatarsus  or  simply  the 
tarsus,  which  bears  the  usually  four-clawed  toes.  One  toe  is 
generally  directed  backward  and  three  forward. 

Where  is  the  knee  in  the  bird?     The  ankle?     Do  you  see  any 

1  Baskett,  "  Story  of  the  Birds,"  p.  33. 


264 


BRANCH    CHORDATA 


advantage  in  this  arrangement?     Why  do  they  differ  from  the 
structure  and  arrangement  in  the  leg  of  man? 

The  body  skeleton  (Fig.  216)  is  strong,  Ught,  and  flexible,  as  it 
must  be  for  flight.     Note  how  firmly  the  vertebrae  are  joined  in 


Fig.  215. — The  most  important  forms  of  birds'  feet  (b,  c,  d,  f,  n,  from  the 
regne  animal) :  a,  Pes  adhamans  of  Cypselus  apus;  b,  P.  scansorius  of  Picus 
capensis;  c,  P.  ambulatorius  of  PJinsinnus  colchicus;  d,  P.  fissus  of  Turdus 
torquatus;  e,  P.  gressorius  of  Alcido  isjiiila ;  /,  P.  insidens  of  Falco  biarmicus; 
g,  P.  colligatus  of  Myderia  scnrijdlcnsis:  h,  P.  cursorius  of  Struthio  camelus; 
i,  P.  palmatus  of  Mergus  mergdm^er;  k,  P.  semipalmatus  of  Recurvirostra 
avocetta;  I,  P.  fissipalmatus  of  Podiceps  cristatus;  m,  P.  lobatus  of  Fulica 
atra;  n,  P.  steganus  of  Phaeton  cetherens.     (After  Claus.) 


the  back.  Note  also  the  very  short  bony  tail,  consisting  of  a 
few  vertebrae  fused  into  the  pygostyle,  which  supports  the  tail 
feathers.  The  oil  gland  is  situated  near  the  pygostyle  and  from 
it  birds  get  the  oil  for  their  feathers.     Note  also  that  the  sternum 


265 


is  keeled  in  our  birds,  while  the  keel  is  lacking  in  the  ostrich. 
The  keel  or  carina  is  a  basis  of  classification.  Birds  with  the 
keel  poorly  or  not  at  all  developed  are  called  Rati' tee,  or  raft-like 
birds,  while  the  keeled  birds  are  called  Carina' tm,  which  group 
contains  our  native  American  birds. 

The  shoulder-girdle  is  a  peculiar  device  of  flying  creatures. 
It  consists  of  the  scapula,  coracoid  process,  and  the  V-shaped 


Fig.  216.^Skeleton  of  a  sparrow:  q,  Quadrate  bone,  peculiar  to  reptiles 
and  birds  and  some  amphibia;  b,  breast-bone;  m,  merry-thought  or  collar- 
bone; c,  coracoid  bone,  over  which  the  tendon  works  to  pull  up  the  wing; 
p,  plowshare-bone,  on  which  the  tail  grows.  Wing-bones:  a,  Upper-arm; 
e,  elbow;  fa,  fore-arm;  w,',  wrist;  t,  thumb;  ha,  hand.  Leg-bones:  th,  Thigh- 
bone; k,  knee;  I,  lower  part  of  leg;  h,  heel;  /,  foot.  (From  Holder,  Amer- 
ican Book  Co.,  Publishers.) 


clavicle,  or  "wish-bone."  The  pelvic  girdle  consists  of  three 
paired  bones,  ilium,  ischium,  and  os  pubis,  Avhich  unite  at  the 
cup  or  acetabulum.,  which  holds  the  head  of  the  femur. 

A  careful  study  of  the  skeleton  of  a  bird  shows  its  marvelous 
adaptation  to  its  uses.  It  must  be  strong  to  support  the  great 
muscles  of  flight  and  to  protect  the  viscera,  while  it  must  be  light 
and  flexible  for  the  purpose  of  aerial  locomotion. 


266 


BRANCH  CHORDATA 


The  Digestive  System. — The  mouth  is  devoid  of  teeth  in  exist- 
ing birds.  Extinct  birds  (see  Figs.  209  and  210)  had  teeth  (see 
Geology) .  Can  the  student  see  any  reason  why  birds  have  lost 
their  teeth?  The  beak  (Fig.  217)  is  very  strong  in  birds  of 
prey,  such  as  the  eagle  and  hawk.     The  mouth  opens  into  the 


Fig.  217. — Forms  of  beaks  (a,  b,  c,  d,  k,  after  Naiimann;  g,  i,  m,  o,  regne 
animal;  I,  from  Brehm) :  a,  Phcenicopterus  antiquoriim;  b,  Platalea  leucorodia; 
c,  Emberiza  citrinella;  d,  Turdus  cyamis;  e,  Falco  candicans;  f,  Mergus 
merganser;  g,  Pelecanus  perspicillahis ;  h,  Recurvirostra  avocetta;  i,  Rhyn- 
chops  nigra;  k,  Columha  livia;  I,  Balceniceps  rex;  m,  Anastomos  coromande- 
lianus;  n,  Pteroglossus  discolor;  o,  Mycteria  senegalensis ;  p,  Falcinellies 
igneus;  q,  Cypselns  apus.     (After  Claus.) 


esophagus,  which  opens  into  the  large  crop,  in  which  the  l^ird  rap- 
idly stores  its  food,  which  is  passed  on  to  the  glandular  stomach 
or  proventriculus.  It  is  then  passed  to  the  muscular  gizzard, 
where  with  the  aid  of  gravel  and  other  hard  substances,  the  food 
is  ground  fine.    The  spleen  is  a  small,  red  ovoid  body  at  the  right 


AVES  2G7 

of  the  proventriculus.  Following  the  gizzard  is  the  duodenum. 
The  pancreas  is  in  a  loop  of  the  duodenum  and  pours  its  secre- 
tion into  it.  The  large  liver  pours  its  bile  into  the  duodenum. 
The  ileum  continues  from  the  duodenum  to  the  large,  straight 
intestine,  the  rectum.  The  junction  is  marked  by  long,  blind 
pouches  or  ceca.  The  large  intestine  ends  in  an  enlargement 
called  the  cloaca,  or  sewer,  because  it  receives  the  undigested 
food,  the  excretions  of  various  organs,  and  the  eggs,  all  of  which 
pass  out  l)y  one  external  opening. 

Circulatory  System. — Circulation  is  complete.  The  heart  is 
large  and  composed  of  two  auricles  and  two  ventricles.  The 
right  aortic  arch  persists  in  birds,  while  the  left  persists  in  man. 
The  circulation  is  double,  pulmonary  and  systemic.  The  sep- 
tum is  complete  between  the  ventricles,  thus  keeping  the  impure 
blood  (venous)  from  the  pure  blood  (arterial). 

The  Respiratory  System. — The  pharynx  opens  by  the  glottis 
into  the  trachea,  which  divides  and  sends  ramifying  branches  into 
the  lungs.  The  lungs  connect  with  the  system  of  air-sacs  which 
aid  the  bird  in  flight.  "Usually  five  pairs  of  these  sacs  are  pres- 
ent, largely  in  the  coelom,  but  extending  in  between  the  muscles 
(breast  and  axillary  region)  and  also  into  the  bones. "^  The 
syrinx  or  voice-box  is  at  the  junction  of  the  bronchial  tubes 
and  the  trachea,  where  they  enlarge  to  form  it.  This  syrinx 
is  especially  well-developed  in  singing  birds. 

Many  of  the  bones  are  hollow  and  filled  with  air.  Thus  is 
the  inspired  air  distributed  over  the  body,  so  that  the  aeration  of 
the  blood  is  not  confined  to  the  limited  area  of  an  orchnary  organ 
of  respiration.  The  bird  is  a  very  warm-blooded  animal,  and  to 
keep  up  its  heat  it  must  use  oxygen  rapidly.  This  it  does  by  its 
rapid  breathing,  which  may  be  at  the  rate  of  sixty  per  minute. 
The  temperature  of  birds  is  from  100°  to  110°  F.,  while  in  man 
the  temperature  is  98.6°  F.  The  temperature  is  also  kept  up  by 
the  non-conducting  feathers  and  by  the  absence  of  skin  glands, 
with  the  exception  of  the  oil  gland  at  the  base  of  the  tail. 

In  the  absence  of  a  diaphragm,  expiration  is  effected  by  the 
drawing  of  the  sternum  toward  the  spinal  column  and  the  bend- 
ing of  the  hinged  ribs.  Inspiration  is  effected  by  the  straighten- 
ing of  the  ribs  brought  about  by  relaxing  the  muscles.  Thus  the 
*  Hertwig. 


268  BRANCH   CHORDATA 

lungs,  which  are  attached  to  the  ribs,  are  alternately  enlarged 
and  contracted. 

The  Excretory  System. — With  each  expiration  the  lungs 
excrete  carbon  dioxid  and  other  waste  products.  The  kidneys 
are  dark-colored,  paired  organs  lying  in  the  pelvic  region  close 
against  the  back.     They  open  into  the  cloaca  by  the  ureters. 

The  Reproductive  System. — Anterior  to  the  kidneys  are  the 
reproductive  organs,  which  open  into  the  cloaca.  Multiplica- 
tion is  by  eggs,  which  are  noted  for  their  very  large  size.  The 
egg  begins  in  the  left  ovary,  the  right  ovary  not  being  developed. 


Fig.  218. — Diagrammatic  longitudinal  section  through  an  undeveloped 
hen's  egg:  Bl,  Germinal  disk;  GD,  yellow  yolk;  WJ),  white  yolk;  DM, 
vitelline  membrane;  EW,  albumen;  Ch,  chalaza^;  S,  shell  membrane;  KS, 
calcareous  shell;  LR,  air-chamber.      (After  Allen  Thompson.) 

It  passes  into  the  oviduct,  where  it  is  fertilized.  As  it  passes  on 
down  this  duct  it  acquires  the  yolk,  the  white,  the  linings,  and 
the  shell  from  glands  that  secrete  these  essential  parts  of  the  egg 
(Fig.  218).  The  birds  are  developed  by  the  large  amount  of 
food  within  the  shell. 

Incubation,  or  sitting  upon  the  eggs  for  a  definite  period  of 
time,  is  peculiar  to  birds,  though  the  python  is  said  to  coil  upon 
its  eggs.  The  number  of  eggs  in  a  clutch  varies  from  one  to  a 
score  or  more.  Some  birds,  like  the  pigeon,  are  monogamous, 
choosing  one  mate  for  life,  but  many  are  polygamous,  like  the 
barnyard  fowls.      It  is  said  that  most  pretty  birds  are  flirts. 


AVES 


269 


The  young  of  some  Inrds  are  altricial  (Fig.  219)  and  must  be 
cared  for  and  fed  by  the  parent  or  parents;  while  others,  hke 


Fig.  219. — The  altricial  nestlings  of  the  blue  jay  {Cyanocit'ta  crista'ta). 
(From  Jordan  and  Kellogg,  "  Animal  Life,"  D.  Appleton  and  Co.,  Publish- 
ers.) 


the  quail,  are  precocial  and  are  able  to  feed  and  care  for  them- 
selves as  soon  as   hatched. 

The  nests  of  birds  vary  much  according  to  the  hal^itat  of  the 
bird  and  the  material  available  (Fig.  220) .  Birds,  like  men,  use 
the  material  they  find  about  them.     Ground  birds  use  the  ma- 


270  BRANCH    CHORDATA 

terial  they  find  on  the  ground,  while  the  arboreal  forms  more 
often  use  small  twigs  for  their  nests,  which  they  sometimes  line 
with  finer  material,  such  as  strings  and  hairs.  The  woodpecker 
uses  no  material  but  the  tiny  chips  he  has  made  in  digging  the 
hole.  The  swift  glues  together  the  twigs  of  its  nest  by  a  sticky 
saliva.  According  to  the  manner  in  which  they  construct  their 
nests,  birds  have  been  variously  styled  weavers,  tailors  (Fig. 
221),  carpenters,  or  masons,  and  their  tools  vary  according  to 


Fig.  220. — Brown  pelican  and  nest  in  young  cabbage  palmetto.     (Photo- 
graph by  Frank  M.  Chapman.)     (Y.  B.  U.  S.  Dept.  of  Agricul.) 


the  work  to  be  done,  or  vice  versa.  Sometimes  both  sexes  build 
the  nest,  or  one  collects  the  material  and  the  other  arranges  it. 
In  other  cases  the  male  sits  by  and  sings,  leaving  the  building 
to  his  mate.  The  position  of  the  nest  varies.  It  may  be  placed 
upon  the  ground,  like  that  of  the  quail,  or  on  a  rock,  like  the 
penguin's,  or  suspended  far  out  on  the  swaying  branches,  like 
the  delicate  hanging  nest  of  the  oriole  (Fig.  222).  The  object 
of  the  position,  of  course,  is  for  protection.    One  must  observe 


271 


how  well  birds  are  protected  by  their  colors,  especially  the  fe- 
male birds  at  nesting  time. 

The  Nervous  System  and  Special  Senses. — The  braiii  (Fig. 
223)  of  birds  is  larger  and  more  highly  developed  than  that  of 
reptiles.  The  cerebrum  and  cerebellum  are  larger.  The  cere- 
brum is  smooth,  but  the  cerebellum  is  convoluted  transversely. 


Fig.  221. — Tailor-bird    (Orthot'omus  suto'rius)  and  nest.       (From  Jordan 
and  Kellogg,  "  Animal  Life,"  D.  Appleton  &  Co.,  publishers.) 


The  eyes  of  the  bird  are  large,  to  meet  the  demands  of  far  vision 
in  flight.  There  are  two  movable  eyelids  and  a  third  membrane 
called  the  nictitating  membrane,  which  the  bird  can  draw  over 
the  eye  by  a  peculiar  muscular  arrangement.  This  membrane 
protects  the  eye  from  too  bright  light  (Fig.  196).  The  pecten, 
"a.  comb-shaped  growth  of  the  coroid  into  the  vitreous  body," 
is  a  peculiar  avian  characteristic.  The  avian  eye  is  character- 
ized not  only  by  the  sharpness  of  vision  consequent  upon  the 


272 


BRANCH    CHORDATA 


Fig.  222. — Baltimore  orioles  and  nest ;  the  mule  in  upper  left-hand  corner 
of  figure.  (From  Jordan  and  Kellogg,  "  Animal  Life,"  D.  Appleton  &  Co., 
publishers.) 


large  size  and  complicated  structure  of  the  retina,  but  also  by  the 
highly  developed  power  of  accommodation,  and  by  the  great  mo- 
bility of  the  muscular  iris  in  the  dilation  and  contraction  of  the 
pupil. 

The  ear  is  well  developed.  There  is  no  external  ear,  but  the 
opening  to  the  tympanum  is  concealed  by  feathers  posterior  to 
the  eye.  The  ear  has  three  semicircular  canals,  the  dilated 
cochlea,  and  a  Eustachian  tube  extending  to  the  mouth  from 
each  ear. 

Of  the  other  senses  it  may  be  stated  that  touch  is  common  in 


AVES 


>73 


all  parts  of  the  body;  that  taste  is  poorly  developed;  that  smell  is 
apparently  not  very  acute,  except  in  vultures  or  turkey  buzzards 
and  other  carrion-eating  birds. 


A  B 

Fig.  223. — Brain  of  the  hen  (A,  from  above;  B,  from  below):  o,  Ol- 
factory bulbs;  6,  cerebral  hemispheres;  c,  optic  lobes;  d,  cerebellum;  d' ,  its 
lateral  parts;  e,  medulla.     (Mter  Carus,  from  Gegenbaur.) 


Behavior  and  Intelligence. — As  has  been  said  of  other  ani- 
mals, it  is  exceedingly  difficult  to  judge  what  goes  on  in  the  mind 
of  a  bird  without  ever  having  been  a  bird.  It  is  very  probable 
that  many  writers  upon  animal  intelligence  give  birds  credit  for 


Fig.  224. — Eye  of  a  nocturnal  bird  of  prey:  Co,  Cornea;  L,  lens;  Rl, 
retina;  P,  pecten;  A'^.o.,  optic  nerve;  Sc,  ossifications  of  the  sclerotic;  CM, 
ciliary  muscle.     (After  Wiedersheim.) 


a  higher  intelligence  than  they  possess  because  they  draw  mis- 
taken conclusions  from  bird  activities,  or,  more  often,  because 
observations  have   been   inaccurate  or   incomplete.     When   a 

18 


274  BRANCH    CHORDATA 

child  performs  a  certain  action,  we  ascribe  to  him  certain  sensa- 
tions, emotions,  or  phases  of  intelhgence.  When  a  bird  does 
the  same  thing,  it  is  only  fair  to  believe  that  these  same  activities 
are  accompanied  by  similar,  though  perhaps  less  distinguishable, 
psychologic  processes.  If  we  deal  fairly,  and  our  observations 
are  complete,  much  may  be  learned  to  add  to  the  meager  informa- 
tion given  in  our  scientific  books  upon  this  fascinating  subject. 
Always  ask  these  questions:  Exactly  what  did  the  bird  do? 
Under  precisely  what  circumstances?  Possible  causes?  Most 
probable  cause?  Does  the  result  of  the  bird's  action  prove  that 
your  conclusion  is  correct? 

Scientists  differ  widely  in  their  opinions  on  bird  mind,  but  it 
is  thought  that  there  is  abundant  proof  that,  in  intelligence, 
birds  stand  next  to  mammals,  if  they  do  not  surpass  some  of  them. 
All  will  surely  agree  that  birds  feel  pleasure  and  pain ;  that  they 
exhibit  surprise,  fear,  sexual  feeling,  sexual  selection,  parental 
affection,  curiosity,  industry,  pugnacity,  anger,  jealousy,  play, 
grief,  and  a  wonderful  homing  instinct.^  Many  examples  are 
recorded  which  seem  to  show  sympathy,  revenge,  recognition  of 
persons,  and  affection  for,  or,  at  least,  attachment  to,  their  human 
friends.  Birds  recognize  their  offspring,  they  have  memory,  as- 
sociation of  ideas,  and  communication  of  ideas.  Examples  are 
given  by  some  of  recognition  of  pictures.  It  is  hoped  that  this 
will  be  further  experimented  with.  Bower  birds  (Fig.  225)  and 
others  show  an  appreciation  of  beautiful  surroundings,  while 
many  birds  seem  to  appreciate  the  brilliant  colors  and  songs  of 
their  mates.  By  experimenting  with  different  colored  foods 
it  has  been  proved  that  birds  can  distinguish  colors  in  objects 
and  that  they  learn  by  experience  and  make  intelligent  choice. 
The  best  possible  treatise  on  the  psychology  of  birds  is  the  living, 
acting  bird  which  every  student  can  have  almost  every  day  in 
the  year.  Study  the  birds.  Make  accurate  observations  and 
record  them.     Weigh  your  conclusions. 

The  Migration  of  Birds. — There  is  no  theory  which  satisfac- 
torily accounts  for  the  periodic  coming  and  going  of  the  birds. 
One  theory  attributes  it  to  the  varying  temperature.  Another 
theory  attributes  it  to  a  lack  of  food,  but  many  of  our  birds  come 
in  March,  when  food  is  still  scarce  and  the  temperature  low,  and 

1  Romanes,  "Animal  Intelligence."     Also  Darwin,  "  Origin  of  Species." 


275 


leave  in  August  or  September,  when  there  is  still  an  abundance  of 
food.  Another  theory  is  that  of  securing  better  and  more  pro- 
tected breeding  grounds.  Nest  concealing  is  possibly  a  factor. 
Chapman  believes  that  the  origin  of  this  great  pilgrimage  "  is 
found  in  the  existence  of  an  annual  nesting  season,"  and  that  it  is 
exactly  paralleled  by  the  annual  migration  of  certain  fishes  to  their 
spawning  grounds,  and  the  regular  return  of  seals  to  their  breed- 
ing-rookeries.     But  what  seems  to  us  most  strange  is  that  the 

.     ...        '/..('  Ill   ,     , 


'  [f 


Fig.  225. — Bower  bird  {Chlamydera  maculata)  with  bower.     (From  Brehm.) 


same  species  of  birds  takes  the  same  definite  route  of  migration 
for  generations,  except  that  its  range  is  gradually  lessened  or 
extended.  Chapman  gives  as  an  illustration  of  the  stability  of 
routes  of  migration  the  bobolinks,  which  aVe  Eastern  birds,  now 
spread  westward  to  Utah,  yet,  instead  of  migrating  directly  south 
through  Texas  and  Mexico,  they,  ''true  to  their  inherited  habit, 
retrace  their  steps  and  leave  the  United  States  by  the  round- 
a-bout  way  of  Florida,  crossing  thence  to  Cuba,  Jamaica,  and 
Yucatan,  and  wintering  south  of  the  Amazon."^  The  extent 
^  Chapman's  "  Bird  Life,"  p.  60. 


276  BRANCH    CHORDATA 

of  these  migrations  varies.  Some  birds  do  not  migrate,  but 
stay  all  winter  in  the  same  locality,  often  changing  from  an 
insectivorous  to  a  seed-eating  life.  Others  migrate  but  short 
distances.  The  snipes  and  plovers  make  extended  migrations, 
going  from  the  arctic  regions  to  the  tropics,  some  species  travel- 
ling from  Alaska  to  Patagonia. 

Parasitism. — The  American  cow-bird  and  European  cuckoo 
lay  their  eggs  in  the  nests  of  other  birds,  where  the  young  are 
cared  for  by  the  foster  parents,  often  at  the  loss  of  their  own  off- 
spring. 

Rivalry  among  birds  may  be  by  means  of  ornament,  color, 
antics,  battle,  or  song.  The  male  is  usually  more  brightly  col- 
ored than  the  female  and  puts  on  his  most  lirilliant  attire  at  the 
courting  season.  Rarely  the  female  is  more  brilliantly  colored 
than  the  male  (see  p.  291).  In  this  case  she  does  the  courting, 
but  as  a  rule  the  female  is  much  more  inconspicuously  colored, 
since  she  is  generally  the  one  which  sits  upon  the  nest,  and  it  is 
to  the  interest  of  the  family  that  she  be  protectively  colored. 
Darwin  believes^  in  the  choice  of  the  female  in  mating,  and  that 
the  attractiveness  of  the  male  may  lie  in  the  tinted  or  lengthened 
beak,  or  the  striped  or  brightly  colored  feet,  or  the  bright  wattles 
or  other  appendages  about  the  head;  but  the  most  common  and 
the  most  brilliant  dis])lay  of  colors  is  in  the  plumage.  Some 
think  that  the  health  and  vigor  generally  may  be  the  cause  of 
this  brilliancy,  but  Darwin  believes  that  it  has  been  intensified 
from  generation  to  generation  by  the  choice  of  the  females,  thus 
perpetuating  these  characteristic  pleasing  colors  and  color-pat- 
terns in  the  offspring.  Mr.  Wallace,  strangely  enough,  denies 
the  female  any  part  in  the  matter  of  mating,  while  he  "ascribes 
to  natural  selection  any  secondary  sexual  character  which  is  of 
practical  use  to  the  male  in  conflict  with  a  rival. "^  Some  birds 
seem  to  be  more  easily  pleased  by  antics  and  pranks  which  are 
sometimes  connected  with  the  display  of  ornament  and  some- 
times not,  as  if  he  who  made  the  biggest  clown  of  himself  was  the 
favored  suitor.^  A  familiar  example  of  the  display  of  beauty- 
spots  is  afforded  by  the  flicker  which  sits  upon  a  twig  facing  his 

1  See  Darwin's  "  Selection  in  Relation  to  Sex,"  "  Descent  of  Man." 

2  Wallace's  "  Darwinism." 

3  Baskett,  "  Story  of  the  Birds." 


AVES  277 

sweetheart,  "lifts  his  wings,  spreads  his  tail,  and  begins  to  nod 
right  and  left  as  he  exhibits  his  moustache  to  his  cliarmer  and 
sets  his  jet  locket  first  on  one  side  of  the  twig  and  then  on  the 
other,  and  she  plays  back  at  him  in  a  similar  peek-a-boo  fashion." 
The  drumming  of  the  grouse  and  the  bill  tattoo  of  the  woodpecker 
are  efforts  to  charm.  Odor  has  no  part  to- play  in  the  art  of 
pleasing  among  birds,  for  the  musk  duck  is  said  to  he  the  only 
bird  which  secretes  an  especially  odorous  substance. 

Battle  among  birds  may  be  for  self-defense  or  for  defense  of 
young,  but  it  is  most  commonly  for  rivalry,  as  both  Wallace  and 
Darwin  believe.  For  bird  battles  there  are  various  kinds  of 
weapons.  The  cassowary  has  the  elongated  inner  toe  armed 
with  a  long  straight  claw  and  the  short  wing  quills  modified  into 
spines.  During  the  nesting  season  many  males  have  wing  spurs 
which  subside  into  something  like  knobs  when  the  season  for  their 
use  is  over.  Unlike  the  bony  wing-spur,  the  leg-spur  is  devel- 
oped from  the  skin.  Some  birds  fight  fiercely,  while  others  merely 
run  a  bluff  by  some  terrifying  attitude,  wherein  they  display 
their  wing-spurs. 

Song. — There  is  much  reason  to  think  that  the  song  of  the 
male  bird  is  a  means  of  pleasing  or  courting  the  favor  of  his 
wished-for  mate,  though  he  afterward  sings  to  cheer  her  during 
the  period  of  incubation.  The  song  often  ceases  when  the 
young  are  hatched;  there  is  something  else  to  be  done  then. 
But  the  song  is  heard  again  during  the  preparation  for  the 
second  brood. 

There  are  many  call-notes  for  other  purposes  than  rivalry. 
Chapman  says  that  "call-notes  form  the  language  of  every  day 
life,  while  song  is  the  outburst  of  special  emotion."  The  call 
of  the  mother  to  her  young  in  warning,  in  fear,  in  reassurance 
when  danger  is  over,  the  cry  of  hunger  or  distress  in  the  young, 
the  thankful  little  chirp  when  feeding  or  when  cuddling  under  the 
mother's  wing,  the  scolding  of  both  parent  birds  when  an  enemy 
approaches  the  nest;  all  these  and  others  have  their  significance 
in  bird  language.  One  would  find  this  study  far  more  interesting 
than  that  of  a  dead  language  and  the  opportunity  for  its 
pursuance  is  present  everywhere.  Try  to  imitate  the  vari- 
ous call-notes  of  the  birds  with  which  you  are  familiar  and  make 
a  list. 


278 


BRANCH  CHORDATA 


Classification. — The  classification  of  birds  seems  to  be  chaotic, 
no  two  zoologists  agreeing.  Some  claim  birds  are  of  too  recent 
origin  geologically  to  have  differentiated  as  yet  into  well- 
marked  orders.  They  might  be  grouped  as  land  birds  and  water 
birds,  or  as  runners  and  flyers,  but  such,  classification  would  not 
be  scientific.  If  there  were  a  geologic  series  showing  the  nat- 
ural affinities,  a  natural  classification  would  be  a  comparatively 
easy  task,  as  all  classification  should  be  based  on  development 
and  structure. 

Division  A.     Rati't^ 

Living  birds  are  divided  into  two  groups,  the  Rati'tce  and  the 
Carina'tce.  Ratitse  are  birds  with  a  raft-like  or  keelless  breast 
bone,  wings  rudimentary  or  too  small  for  flight,  legs  large, 
strong,  and  fitted  for  rapid  running.     As  examples  may  be 


Fig.  226. — Ap'teryx  austral'is,  a  nocturnal  flightless  bird  with  nostriLs  near 
the  end  of  the  bill.  The  external  wing  is  shown  in  the  upper  part  of  the  cut. 
(Romanes.) 

named  the  ostrich,  emu,  rhea,  cassowary,  kiwi  (Fig.  226),  and 
the  extinct  moa  and  other  ostrich-like  birds.  None  of  these 
birds  is  native  to  the  United  States,  but  in  recent  years  they 
have  been  imported  into  some  parts  of  the  west,  as  Pasadena, 
California,  Salt  River  Valley,  Arizona,  and  some  other  dry,  warm 


279 


localities,  where  they  are  breeding  and  Ijeconiing  of  much  value 
for  their  plumes. 

The  ostrich  is  the  largest  of  living  birds  (Fig.  227).  It  may 
attain  to  a  height  of  6  or  8  feet,  and  may  easily  reach,  with 
outstretched  neck,  a  height  of  10  feet.  It  weighs  from  375  to 
450  pounds.     It   is  a  rapid  runner,  a  single  stride  is  said  to 


i0^' 


Fig.  227.— Ostrich  twentv-six  months  old.     (Year-book  U.  tS.  Dept.  Agri- 
cul.,  1905.) 


cover  25  feet  or  more.^  It  uses  its  two-toed  feet  in  defense  and 
its  kick  is  dangerous.  "The  cry  is  said  to  be  hoarse  and  mourn- 
ful, resembling  the  roar  of  a  lion  or  the  lowing  of  an  ox."  The 
eggs  are  5  or  6  inches  in  length,  and  one  ostrich  egg  equals  a 
score  of  common  hen  eggs.  They  are  laid  in  a  hollow  nest  in 
1  Evans,  "  Birds,"  p.  28. 


280  BRANCH    CHORDATA 

the  soil  or  sand  and  one  nest  may  contain  as  many  as  twenty- 
five  or  thirty  eggs,  several  hens  laying  in  one  nest.  The  male 
does  most  of  the  incubating,  the  eggs  hatching  in  from  forty  to 
forty-five  days.  The  ostrich  is  a  native  of  Africa.  It  is  found 
from  Barbary  to  Arabia  and  even  into  Mesopotamia,  where  it 
has  long  been  domesticated.  "The  plumes  are  plucked  or, 
preferably,  cut  twice  a  year."     The  flesh  is  coarse  and  little 


Fig.  22S.— Ostriches  five  days  old.     (Year-book  U.  S.  Dept.  Agricul.,  1905.) 

used.     The  yearly  sales  in  South  Africa  amount  to  nearly  five 
million  dollars. 

The  three-toed  rhea,  or  so-called  ostrich,  is  a  South  American 
bird.  Rheas  are  shorter  than  the  ostrich  and  the  feathers  are 
rounded  and  very  soft.  Their  favorite  haunts  are  the  "treeless 
flats  of  the  Argentine  Pampas,  the  scrub-covered  plains  of  Pata- 
gonia, or  the  dry  open  sertoes  of  Brazil."^ 

The  cassowaries  and  emus  have  rudimentary  \vings,  and  they 
lack  the  ornamental  wing  and  tail  plumes.  The  hair-like  coat 
is  characteristic.  The  female  cassowary  is  larger  than  the  male, 
and  both  sexes  are  black.  The  plumage  is  made  into  rugs,  mats, 
and  head  ornaments. 

^  Evans,  "  Birds." 


WATER    BIRDS  281 

Division  B.     Carinat^ 

This  group  contains  the  birds  with  a  keeled  breast-bone.  It 
is  usually  divided  into  seventeen  orders  by  American  ornitholo- 
gists. The  orders  of  l)irds  are  not  well  differentiated  as  compared 
with  the  reptilian  orders.  The  classification  followed  for  Car- 
inatae  is  that  of  Reed  and  Chapman  in  their  "Color  Key  to  North 
American  Birds." 

WATER   BIRDS 

Order  I.  Pygop'odes. — Auks,  grebes,  and  loons  are  examples  of 
this  order  of  marine  birds.  Their  legs  are  situated  far  back  on 
the  body,  the  feet  are  broadly  webbed,  and  the  bills  are  narrow. 
They  are  good  swimmers  and  divers,  and  some  are  good  flyers. 


Fig.  229. — Great  penguin  {Aptenody'tes  patagon'ica.)      (After  Tenney.) 

The  penguins,  of  which  there  are  about  twenty-eight  species,  are  found 
in  the  Antarctic  region  and  on  the  South  American  coast  (Fig.  229). 
When  on  land  these  birds  rest  on  the  whole  metatarsus  and  assume  an  erect 
attitude,  their  legs  being  situated  very  far  back.  They  are  famous  swim- 
mers and  divers,  but  they  cannot  fly.  Their  wings  are  degenerate,  being 
really  feathered  flippers.     These  feathers  in  some  species  look  more  like 


282 


BRANCH  CHOKDATA 


scales. 1  When  under  water  the  wings  act  as  paddles  and  the  feet  as  rud- 
ders. Penguins  are  gregarious,  swimming  in  schools,  and  are  seldom 
seen  on  land  except  at  the  breeding  season,  when  they  go  in  great  numbers 
to  their  rookeries.  The  nests  of  grass  and  leaves  may  be  under  stones  or 
in  caves  or  burrows.  The  male  assists  in  incubating  the  two  white  or 
greenish  eggs,  which  require  six  weeks  to  hatch.  The  young  are  blind  and 
altricial,  and  are  fed  by  the  parents,  which  insert  their  bills  in  those  of  the 
young.  The  food  of  the  penguin  consists  of  crustaceans,  mollusks,  and 
fishes  with  a  small  amount  of  vegetable  matter.  The  voice  may  be  a 
hoarse  bark,  "  croak  or  scream,  or  a  murmuring  sound,  or,  in  the  young,  it 
may  be  a  whistle." 

Order  II.  Longipen'nes. — These  are  mostly  sea  birds,  with  loi;g 
wings  and  webbed  feet.     Gulls  and  terns  may  be  named  as  ex- 


Fig.  230. — Franklin  gull;  15  inches.     (Photographed  from  specimen.) 


amples  of  this  order  (Fig.  230).     Gulls  feed  chiefly  on  fish,  but 

one  may  observe  hundreds  of  them  about  an  ocean  liner  as  it 

comes  into  port.     They  seek  what  is  thrown  overboard.     They 

1  Hornaday. 


WATER    BIRDS 


are  the  scavengers  of  the  water,  feeding  from  the  surface, 
are  at  home  m  the  open  seas. 


283 
Gulls 


Terns  are  littoral  {Fig,.  231).  They  are  more  slender  and  active  than  the 
gulls,  and  have  long  forked  tails  and  pointed  bills.  They  nest  in  colonies, 
coming  from  the  South  in  May  and  remaining  until  September.  When 
in  search  of  food  the  terns  fly  with  the  bill  downward,  while  gulls  carry  the 
bill  in  a  line  with  the  body.     Terns  nest  in  colonies  on  islands.     The  nest 


/7,-» 


Fig.  231. — Terns  in  Southwest  Harbor  Kev  in  Breton  Island  Reservation. 
(Year-book  U.  S.  Dept.  Agricul,  1905.  '  Photo  by  Frank  M.  Miller.) 

is  made  of  a  few  wisps  of  grass.  The  eggs,  two  or  three  in  number,  are 
laid  in  a  depression  in  the  sand  or  pebbles.  The  young  of  both  gulls  and 
terns  are  precocial.  When  frightened,  both  gulls  and  terns  squat  low 
near  the  ground  and  remain  motionless  until  actually  touched. 


Order  III.  Tubina'res  are  so  called  because  the  nostrils  are 
carried  well  forward  through  the  two  round  tubes  that  lie  either 
along  the  top  or  the  sides  of  the  bill.     The  opening  of  the  nostril 


284 


BRANCH    CHORDATA 


is  about  half-way  between  the  base  and  the  tip  of  the  bill.  The 
bill  is  hooked  like  that  of  a  ])ird  of  prey.  "All  are  deep-water 
birds,  strong  of  wing,  and  brave  spirited  beyond  all  other  birds. 
The  range  of  the  order  is  worldwide.  The  most  of  them  are 
found  in  the  southern  oceans." 


To  this  order  belong  the  petrch,  "  Mother  Carey's  chickens,"  which  one 
sees  hundreds  of  miles  out  on  the  ocean.  The  stormy  petrels  are  the  smal- 
lest of  web-footed  birds,  being  no  larger  than  catbirds.  Their  note  is  shrill, 
and  their  flight  butterfly-like. 

The  wandering  albatross,  with  an  expanse  of  wing  from  10  to  14  feet, 
is  also  a  member  of  this  order.  It  is  a  wonderful  flyer,  sailing  for  hours  with- 
out resting,  always  with  rigid,  motionless  wings,  rising,  descending,  or  turn- 
ing without  a  visible  movement  of  them.  It  has  been  made  immortal  by 
Coleridge's  "  Rime  of  the  Ancient  Mariner." 


^^^ 


Fig.  232. — A  little  corner  of  Pelican  Island.     (Year-book  U.  S.   Dept. 
Agricul.,  1905.) 


Order  IV.  Steganop'odes. — The  members  of  this  order  have 
the  four  toes  connected  by  a  web.  The  bill  has  no  lamellce. 
The  nostrils  are  small  or  wanting  and  the  throat  is  usually 
pouched.  Here  l)elong  such  large  aquatic  birds  as  the  frigate 
or  man-of-war  bird,  the  cormorant,  and  the  pelican. 


WAT  TOR    BIRDS  285 

The  frigate  or  man-of-war  bird  is  a  very  long-winged,  long-tailed  bird 
of  the  ocean.  Its  legs  are  very  weak,  but  it  is  a  remarkable  flyer.  It  is 
found  hundreds  of  miles  from  shore  on  the  ocean.  These  birds  live  in  the 
southern  waters  of  both  hemispheres.  In  the  Cocos-Keeling  Islands, 
Mr.  H.  O.  Forbes  says,  they  gain  their  living  b}^  forcing  other  fishing  birds, 
like  the  gaiin(>ts  and  noddy  terns,  to  disgorge  the  fishes  they  have  caught. 

The  cormorants  are  large,  green-eyed,  marine  hlackl)ir(ls.  They  are 
common  aloii^  the  seashore.  They  feed  chiefly  on  fish  and  are  gregarious. 
Their  gular  pouch  is  rudimentary  as  compared  with  that  of  the  pelican. 
The  Chinese  tame  the  cormorant  and  use  it  in  catching  fish.  The  pelican 
is  used  for  a  like  purpose  in  the  East  Indies. 

The  pelicans  are  large  birds,  with  very  large  bills  and  immense  gular 
pouches  in  which  they  catch  the  fish  upon  which  they  feed.  The  brown 
pelican  {Peleca'nus  fus'cus)  of  Florida  is  a  sociable  bird,  about  4  feet  in 
height.  It  does  not  acquire  its  full  colors  until  its  third  year.  The  neck 
of  the  adult  bird  is  in  two  colors,  white  and  a  rich  blackish  brown.  The 
back  is  a  beautiful  silvery  gray-brown  effect  composed  of  many  tints. 
The  top  of  the  head  is  white  or  yellowish,  the  pouch  a  bluish  purple  or 
greenish.  The  bill  is  a  foot  long  and  demands  and  supplies  four  pounds  of 
fish  each  day.  Pelican  Island,  Florida,  is  the  government  reservation  for 
these  birds  (Fig.  232). 

The  California  brown  pelican  {Peleca'nus  call  for' nicus)  is  found  along  the 
Pacific  coast  from  Galapagos  to  British  Columbia.  The  beautiful  great 
white  pelican  (P.  erythrorhyn'chos)  is  now  rare.  It  is  found  in  large  western 
inland  lakes  and  in  the  Yellowstone  National  Park.  The  male  has  a  pe- 
culiar knob  on  the  bill  during  the  breeding  season  only. 


Order  V.  An'seres. — These  birds  have  flat,  lamellated  bills 
(Fig.  233).  The  body  is  rather  flat.  The  legs  are  far  back  on 
the  body,  causing  them  to  waddle  when  they  walk  and  making 
them  good  swimmers.  Their  toes  are  webbed.  The  feathers 
are  well  oiled  so  they  can  go  into  the  water.  Geese  spend  less 
time  in  the  water  than  ducks  do.  The  food  is  largely  vegetable. 
The  swans,  geese,  and  eider  duck  do  not  dive  in  feeding,  l)ut 
thrust  the  head  and  neck  under  water,  sometimes  tipping  up  the 
body.  Marine  ducks  are  expert  divers.  The  wild  geese,  ducks, 
and  brant  are  migratory,  but  they  are  not  so  numerous  as 
formerly,  since  so  many  have  been  slaughtered  for  market  and 
sport 

The  swan  belongs  to  this  order  and  is  the  largest  of  the  Anseres.  In 
fact,  it  is  one  of  our  largest  birds.  Hornaday  says  it  is  pugnacious  and 
quarrelsome.  The  plumage  of  the  trumpeter  swan  is  white;  the  bill  and 
feet  are  black.  The  young  are  a  dirty  gray.  The  "  voice  is  like  a  blast  from 
a  French  horn,"  but  is  musical  when  given  by  a  large  flock  in  chorus.  The 
range  is  from  the  Gulf  to  the  fur  countries.  They  breed  from  Iowa  north 
and  west  to  the  Pacific  coast. 


286  BRANCH    CHORDATA 

Order  VI.  Odontoglos'sae. — The  American  flamingo,  of  the 
warm  parts  of  the  Atlantic  coast,  is  our  representative  of  this 
order.  It  is  a  large,  web-footed,  long-necked,  wading  bird. 
The  color  varies  from  rose  to  vermilion.  It  has  a  heavy,  bent, 
lamellated  bill,  with  which  it  scoops  up  and  crushes  small  mol- 
lusks  and  crustaceans,  on  which  it  feeds.  Its  webljed  feet  are 
used  more  for  support  in  walking  on  the  soft  mud  than  for  swim- 


Fig.  233. — Ring-necked  duck  {Aythya  collaris);  17  inches.     (From  speci- 
men.) 

ming.  Flamingoes  nest  in  colonies.  A  colony  visited  l)y  Mr. 
Chapman  contained  upward  of  two  thousand  nests.  One  or 
two  eggs  make  up  a  clutch.  The  voice  is  a  vibrant  honking, 
like  that  of  a  wild  goose. 

Order  VII.  Hero'diones. — This  order  is  represented  by  such 
birds  as  the  storks,  herons,  ibises,  and  spoon-bills.  They  are 
long-billed,  long-necked,  long-legged,  wading  birds,  with  short 
tails  and  broad,  rounded  wings.      They  frequent  the  water  and 


WATER    BIRDS 


287 


seize  their  prey,  be  it  fish  or  frog,  with  tlieir  long  sharp  bills. 
The  young  are  altricial. 

There  are  probably  twenty  species  of  storks,  all  but  two  of  which  are 
found  in  the  Old  World.  The  migratory  stork  of  Europe  is  the  most  famous. 
Their  clumsy  nests  are  known  over  the  world. 


Fig.  234. — American  egret  (Ard'ea  egret' ta).     Length,  41  inches.     (Photo- 
graph from  specimen  with  neck  extended.) 


The  herons  are  variously  called  the  bittern,  the  great  blue  heron,  the 
green  heron,  the  great  white  egret,  and  the  "  squawk."  Many  have 
ornamental  crests  and  plumes.  Some  herons  stand  in  waiting,  while 
others  run  rapidly  and  noisily  through  the  water,  depending  on  their 
agility  in  capturing  their  prey.  Some  stalk  slowly  and  silently  along  in 
shallow  water,  the  head  carried  in  front  in  a  line  with  the  shoulders,  and 
the  large  eyes  scrutinizing  every  object  in  the  water.  Herons  and  ibises 
are  gregarious,  nesting  and  roosting  in  flocks,  but  feeding  individually. 


288 


BRANCH  CHORDATA 


The  heronry  or  rookery  is  located  in  low  trees  on  a  small  island  or  marsh. 
Bitterns  are  found  singly  or  in  pairs. 

The  liiTons,  egrets, 1  and  ibises  have  been  so  persistently  hunted  for  their 
pluiiits  iliai  some  species  are  now  quite  rare.  The  snowy  heron  {Ard'ea 
catididi.s'xinid)  and  the  American  egret  {Ard'ea  egret' ta)  (Fig.  234)  are 
the  most  beautiful  of  these.     Their  black  legs  and  bills  only  intensify  the 


Fig.  235. — Sand-hill  crane  {Grus  mexica'na). 
specimen.) 


Length,  44  inches.     (From 


snowy  whiteness  of  their  plumage.  The  filmy  aigrettes  are  like  spun  glass. 
These  number  about  fifty  and  are  worn  by  the  mother  during  the  breeding 
season  only.  To  obtain  these  plumes  the  mother  must  be  shot,  and  the 
nestlings  are  left  to  perish  simply  to  gratify  the  vanity  of  thoughtless 
women.  The  sale  of  these  aigrettes  in  the  United  States  is  now  forbidden 
by  law. 

^  Apgar's  "  Birds  of  the  United  States." 


WATER    BIRDS 


289 


Order  VIII.  Paludic'olae,  as  the  name  indicates,  are  marsh- 
inhabiting  birds.     The  crane  is  a  famihar  example. 

The  coot,  or  mud-hen,  is  abundant  in  reedy  swamps,  near 
small  creeks  and  shallow  lakes.  It  is  an  excellent  swimmer.  Its 
foot  is  scalloped  or  only  half-webbed.     It  is  omnivorous. 

The  rails  and  cranes  resemble  large  or  overgrown  Limicoloe.  The  young 
are  precocial.     These  birds  usually  feed  on  surface  materials  rather  than 


Fig.  236. — A  valuable  bini  in  d  m)j,i  i  m  i  miik  tion — field  plover.     (Year- 
book, U.  S.  Dept.  of  Agntul.,  1907.) 


by  probing  in  the  mud,  as  the  plovers  and  snipes  do.  The  rails  are  chiefly 
marsh  or  swamp  birds  of  medium  or  small  size.  The  Virginia  rail  is  a  little 
smaller  than  a  quail.  "  He  is  an  odd-looking  bird,  with  a  half-quizzical, 
half-cynical  expression.  His  eyes  are  blood  red  and  deeply  sunk  in  the 
long,  narrow  head." 

The  cranes  (Fig.  2.35),  of  which  there  are  but  three  species  in  North 
America,  are  easily  distiiiguislied  by  the  long  bill,  long  head,  very  long  neck, 
short,  broad  wings,  short  tail,  and  very  long  legs.  They  fly  in  single  file 
with  legs  and  neck  outstretched.  The  cranes  resemble  the  rails  in  general 
structure,  but  the  herons  in  external  form. 
19 


290  BRANCH    CHORDATA 

The  whooping  or  white  crane  is  now  very  rare.  A  full-grown  one  is 
4^  feet  high.  Hornaday  says  its  trumpet  call  will  carry  as  far  as  the  roar  of 
a  lion.  The  sand-hill  or  brown  crane  ranges  from  the  Gulf  to  Manitoba. 
The  nests,  of  roots,  rushes,  and  weeds,  are  made  on  the  ground  and  usually 
contain  two  eggs.  Goss  says  "  during  courtship  and  the  early  breeding  sea- 
son their  actions  and  antics  at  times  are  ludicrous  in  the  extreme,  bowing 
and  leaping  high  in  the  air,  hopping,  skipping,  and  circling  about  with 
drooping  wings  and  croaking  whoop,  an  almost  indescribable  dance  and 


'  WljZ. 


Fig.  237. — Long-billed  curlew  ( Nume'nius  longiros'tris) ;  23  inches.    (Photo- 
graph from  specimen.) 

din,  in  which  the  females  (an  exception  to  the  rule)  join,  all  working  them- 
selves up  into  a  fever  of  excitement  only  equalled  by  an  Indian  war  dance, 
and,  like  the  same,  it  only  stops  when  the  last  one  is  exhausted." 

Order  IX.  Limic'olae. — These  are  small  or  medium-sized  birds, 
usually  brown  or  gray,  with  some  white  in  their  plumage.  The 
bill  is  long  and  slender  and  the  legs  spindling.      Except  in  a 


LAND    BIRDS  291 

few  species  the  tibia  is  bare  of  feathers,  sometimes  almost  to  the 
knee.  With  a  single  exception,  the  hind  toe  is  short  and  elevated 
or  lacking.  There  are  about  125  species  of  these  shore  birds,  or, 
as  their  original  name  suggests,  mud-dwellers,  of  which  75  live 
in  America,  north  of  Mexico. 

The  Phal'aropes  are  small  in  size  and  in  number  of  species,  of  which  there 
are  but  three.  These  lobe-toed  birds  have  this  peculiar  characteristic: 
the  female,  which  is  larger  and  more  brightly  colored  than  the  male,  does 
the  courting.  The  male  does  the  incubating  and  cares  for  the  young, 
which  are  soon  able  to  swim  and  to  hunt  their  own  food. 

Snipes  and  plovers  (Fig.  236)  are  much  sought  for  game  birds  in  some 
regions.  The  young  are  precocial.  They  afford  some  fine  examples  of 
protective  resemblance.  One  may  be  very  near  a  snipe  and  not  see  it  if 
it  only  keeps  still,  so  perfect  is  its  resemblance  to  its  surroundings. 

The  Jack  snipe  {Gallina'go  delica'ta)  and  the  American  woodcock 
(Philohe'la  minor)  have  shorter  legs  and  the  eyes  are  farther  back  on  the 
heads  than  in  any  other  birds.  Their  long,  straight  bills  have  sensitive 
tips,  with  which  they  probe  down  into  the  mud  for  earthworms.  Horna- 
day  describes  the  shrill  cry  of  the  Jack  snipe  when  it  rises  as  a  half -scream, 
half-squawk.  Its  range  is  large,  extending  all  through  the  United  States, 
except  in  arid  regions. 

The  avocet  or  stilt  {Recurviro'stra  americana)  is  like  a  snipe,  but  the  legs 
and  bill  are  much  longer  than  those  of  a  snipe. 

The  curlews  (Fig.  237),  sandpipers,  and  oyster-catchers  also  belong  to 
this  order. 

A  plover  {jEgiali'tis  vocif'era),  commonly  called  killdeer,  is  found  through- 
out the  temperate  portion  of  North  America.  They  are  quite  common 
birds  in  the  Mississippi  Valley.  Though  scattered  when  feeding,  they  fly 
in  flocks. 

LAND   BIRDS 

Order  X.  Galli'nae. — This  order  includes  many  birds  val- 
uable to  man,  as  pheasants,  pea-fowls,  guineas,  chickens,  turkeys, 
quails  (Fig.  238),  and  prairie-chickens.  The  birds  of  this  order 
are  chiefly  ground  birds,  living  largely  on  seeds  and  grains,  hence 
the  crop  and  gizzard  are  well  developed.  Their  bodies  are  robust, 
their  wings  rather  short,  the  legs  stout,  and  the  feet  clawed. 
The  bills  are  short  and  stout.  They  are  poor  flyers,  often  going 
with  a  "  whirr."  In  the  wild  forms  the  protective  resemblance 
is  almost  perfect,  their  colors  l)lending  with  the  grass,  brush,  and 
weeds  in  which  they  live.  The  ptarmigan  (Fig.  239)  changes 
color  with  the  season  to  suit  its  environment,  being  white  in 
winter.  The  males  of  this  order  usually  have  conspicuous  mark- 
ings on  the  head,  as  the  rooster's  comb  and  wattle,  and  the  red 
head  of  the  turkey  gobblers,  or  conspicuous  plumage,  as  the  pea- 


292 


BRANCH    CHORDATA 


cock.     They  are  polygamous, 
males  fight  fierce  battles. 


The  rivalry  is  keen  and  the 


The  only  native  bird  of  the  pheasants  is  the  wild  turkey,  now  almost 
extcrniinatcd  hy  llic  sportnieii,  hein^  foun<l  in  a  few  regions  of  the  Eastern 
anil  Soul  hern  Stales,  ami  in  ( tklahonui  and  Texas.  Several  pheasants  have 
been  inlroduced  into  lliis  countrN'  from  China.  The  eonnnon  chickens  are 
descendants  of  the  jungle  fowl  of  India  {(lallus  bankivus). 

The  grouse  family  all  nest  on  the  ground'.  Their  colors  are  chiefly  brown 
and  gray,  so  they  rely  on  concealment  for  protection.  The  "  whirr  " 
accompanying  flight  is  caused  by  the  beating  of  their  small  concave 


Fig.    238. — Quail    {Coli'nus  virijinia'nus);    10  inche: 
specimen.) 


(Photograph  from 


To  this  family  belong  the  bob-white  or  "  quail,"  the  .sage  grouse  of  the 
West,  and  the  once  cominon  i)r,iirie-hen  of  I  lie  ,Missi.ssippi  \'alley.  The 
male  prairie-chicken  h.ns  peculiar  salmon-colored  air-sacs  on  lh(>  sides  of  his 
neck  which  he  inflates  in  making  his  "  bum-bum-boo  "  as  he  struts  and  bows 
to  his  prospective  mate  in  the  courting 


Order  XI.  Colum'bae. — This  order  is  represented  in  the  United 
States  by  the  pigeons  and  doves.  There  are  about  300  species 
in  the  world,  but  only  ten  or  eleven  in  the  United  States.  The 
head  is  small  and  round,  the   bill  and  legs  short,  the  body 


LAND    BIRDS  293 

plump,  and   the   plumage  has  a  peculiar  iridescence.      Some 
live  on  the  ground,  others  in  trees,  and  still  others  in  open  places. 

The  turtle  dove,  or  mourning  dove,  is  one  of  our  commonest  species  and 
its  plaintive  cooing  is  quite  familiar  to  all.  It  breeds  throughout  the 
United  States,  and  one  often  meets  it  in  the  country  roads.  It  is  one  of  the 
farmer's  useful,  as  well  as  beautiful,  friends.  Three  stomachs,  examined 
at  Washington,  were  found  to  contain  23,100  weed  seeds. 

Darwm  viys  our  domestic  pigeons  oiigmatod  from  th(  biu(-ro(iv  pigeon 
{Colum'ha  liv'ui)  1  h(  \n  -.1  ol  i  lu  i)igeon  is  a  flimsy  one  of  t\\  igs,  on  which 
it  lays  two  white  •gg'^,  iiom  whi(h  Intdi  the  naked,  altiHial  "squabs." 


'v^i^-X     Winter  ^-^^^^  ^"'•i^-^ —      -"^     iUMMts 

Fig.    239. — Seasonal   changes   of    color   in  ptarmigan  (Logo' pus  mii'tus); 
^  natural  size.     (Romanes.) 

Both  sexes  incubate.  The  young  are  fed  on  "  pigeon's  milk,"  the  parent 
thrusting  its  bill  into  the  mouth  of  the  young  and  discharging  therein 
food  which  has  been  softened  in  its  own  crop.  Chapman  and  liccd  say 
also  that  some  species  of  pigeons  nest  in  isolated  pairs  and  other  species  in 
large  colonies.  If  you  have  ever  watched  a  pigeon  drink,  you  know  that  it 
liolds  th(-  ))ill  in  the  water  till  it  lias  finished  drinking.  The  Carrier  pigeon 
is  a  variety  of  the  domestic  ])ig(M)n  used  to  carry  messages.  The  Wild  or 
Passenger  pigeon  (Evl(ti)is'ti  s  miqrdto'rius)  was  formerly  very  abundant. 
In  1808  Wilson  estimated  one  flock  at  over  2,000,000,000  pigeons.  They 
are  now  almost  extinct,  anotlicr  result  of  the  hunter  and  his  gun. 

Allied  to  the  pigeons  was  the  extinct  dodo  of  Madagascar.  It  was  a 
giant  compared  to  our  pigeons.  Look  up  a  picture  of  it^  and  see  what  a 
strange  looking  bird  it  was.     It  could  not  fly. 

1  Evans,  "Birds,"  p.  329. 


294 


BRANCH  CHORDATA 


Order  XII.  Rapto'res. — These  are  usually  large,  strong  birds, 
with  hooked  bill  and  strong  claws  for  seizing  and  holding  their 
prey,  which  consists  of  fish,  Inrds,  rats,  mice,  and  other  small 
mammals.  To  this  order  belong  hawks,  eagles,  condors,  buz- 
zards, vultures,  and  owls. 


Fig.  240.— Bui 
way);  34  inches, 
cul.,  1906.) 


eagle   {Ildliiu'lus  Uucuccph'alus)   (drawn  by  R.  Ridg- 
(Bulletin  27,  Biological  Survey,  U.  S.  Dept.  of  Agri- 


The  hawks  and  eagles  (Falcon' ida')  (Fig.  240)  comprise  about  three  hun- 
dred and  fifty  species  and  include  such  birds  as  the  kites,  hawks,  buzzards, 
antl  the  osprey  or  fish-hawk.  These  are  almost  exclusively  carnivorous. 
Raptores  are  easily  distinguished  by  their  hooked  bills  and  sharp  talons. 
They  feed  chiefly  on  rats  and  mice.  Occasionally  some  of  the  hawks  will 
attack  chickens,  but  there  are  more  friends  than  foes  among  them.  Hawks 
build  large  nests  of  sticks  in  tall  trees.  They  lay  four  whitish  eggs  with 
brown  blotches. 


LAND    BIRDS  295 

The  sharp-shinned  hawk  is  small  (l('ii>i;th,  1 1 1  inohos),  with  a  long  square 
tail  marki'd  hy  widfly  scparalcd  dark  hands  across  it,  the  widest  one 
nearest  the  end.  Tlie  principal  food  is  sonjz;  birds,  so  this  hawk  should  be 
destroyed  wherever  found.  Cooper's  hawk  is  dark  brown  with  grayish  and 
brownish  spotted  under  parts.  Its  tail  is  round.  In  food  habits  it  is  much 
like  the  sharp-shinned  hawk,  and  it  should  be  destroyed. 

The  red-tailed  hawk  (Fig.  241),  more  often  called  tlK>  ehieken-hawk,  is 
a  great  destroyer  of  injurious  mammals.  Poultry  and  other  birds  do  not 
constitute  10  [)er  cent,  of  this  hawk's  food,  and  all  other  beneficial  animals 
which  it  eats  added  do  not  make  15  per  cent.  So  its  record  is  85  per  cent, 
as  a  friend,  against  15  per  cent,  as  an  enemy,  of  the  farmer. 


Fig.  241.— Red-tailed  hawk  (much  nnluced).    Length,  21  inches.     (Bulle- 
tin 17,  Biological  Survey,  1902.) 

Owls  in  America  north  of  Mexico  number  eighteen  species.  "  They  vary 
in  size  from  the  tiny  elf-owl  of  Arizona  (only  6  inches  long)  to  the  great  gray 
owl  of  the  Arctic  regions  (.30  inches  long).  The  owls  (Fig.  242)  {Bubon'id'cp. 
and  Strig'idce)  have  a  soft  plumage,  hence  their  silent  flight.  Their  eyes  are 
large  and  dilatable,  enabling  them  to  see  well  at  night.  The  face  is  so 
broad  that  both  eyes  look  forward.  They  are  immovable,  so  that  to  look 
in  another  direction  the  head  must  be  turned.  They  have  a  peculiar  voice, 
a  screech  in  our  little  screech  owl  and  a  "  who-hoo-whoo  "  in  the  great 
horned  owl.  When  one  is  camping  in  the  woods  the  sound  of  this  bird 
gives  one  queer  creepy  feelings  until  one  knows  what  is  making  it.  Owls 
live  chiefly  on  rats,  mice,  frogs,  snakes,  and  rabbits.     Some  of  the  smaller 


296  BRANCH    CHORDATA 

ones  devour  many  grasshoppers  and  other  insects.  They  regurgitate  the 
indigestible  portions  of  their  prey  in  httle  oblong  balls  or  pellets,  which  may 
he  found  on  the  ground  under  the  trees  in  which  they  nest.  Owls  nest  in 
holes  in  trees  or  banks,  and  lay  from  three  to  five  pure  white  eggs.  They 
feed  at  night  when  the  rats  and  mice  are  about.  Thus  they  are  of  more 
benefit  than  the  day-feeding  hawks. 

The  great  horned  owl  is  the  only  species  which  is  harmful  to  man,  and 
even  it  pays  sonu'thing  for  its  chickens  with  the  mice  and  rats  it  kills. 
"  Mr.  O.  E.  Niles,  of  Ohio,  once  found  in  a  nest  of  this  bird  several  full-grown 


Fig.  242. — Barn  owl  (Strix  prntin'cola).     (Photograph  from  specimen.) 

Norway  rats,  and  on  the  ground  under  the  tree  containing  the  nest  he  found 
the  bodies  of  113  rats."i  Now  how  many  chickens  would  that  number  of 
rats  eat  in  a  year?  Probably  more  than  one  great  horned  owl  would  eat, 
and  a  lot  of  corn  besides.  The  investigations  at  Washington  prove,  how- 
ever, that,  although  many  rats  and  mice  are  eaten,  so  many  small  birds 
and  domestic  fowls  are  destroyed  by  it,  that  one  is  justified  in  shooting  the 
great  horned  owl. 

Burrowing  owls  (see  Prairie  dogs)  nest  in  the  abandoned  nests  of  prairie 
dogs,  but  do  not  live  in  the  same  nest  with  them. 
1  Hornaday,  p.  223. 


LAND    BIRDS 


297 


Order  XIII.  Psit'taci. — Parrots  or  paroquets  are  usually 
highly  colored,  harsh-voiced  tropical  birds,  with  thick,  stout 
bills.  The  upper  half  of  the  bill  extends  down  over  the  lower  one. 
The  toes,  which  are  used  as  hands,  or  with  which  they  walk  or 
climb,  are  arranged  two  in  front  and  two  behind.  There  are 
about  500  species  of  these  birds.  They  live  on  fruits  and  seeds. 
They  are  of  considerable  commercial  importance.  The  parrot 
is  quite  a  common  pet.  The  Carolina  paroquet  is  the  only 
species  found  native  in  the  United  States.     Its  range  formerly 


Fig.  243. — Belted  kingfisher  {Cer'yle  alcyon); 
from  specimen.) 


13  inches.     (Photographed 


extended  to  the  Great  Lakes,  but  now  it  is  found  only  "  rarely 
in  Florida  and  along  the  Gulf  coast  to  Indian  Territory." 

Order  XIV.  Coc'cyges. — This  is  an  Old  World  order  of  trop- 
ical birds,  "classified  together  in  one  miscellaneous  group  only 
because  they  belong  to  no  other  order." 

Kingfishers  are  a  large  family  of  about  two  hundred  species,  chiefly  of 
tropical  birds,  represented  in  the  United  States  by  three  species.  The 
belted  kingfisher  (Fig.  243)  is  our  common  species,  described  by  Apgar  as 
"  a  noisy,  short-tailed,  large,  straight-billed,  crested,  blue-backed  bird,  with 
white  lower  parts  and  a  bluish  band  across  the  breast." 


298 


BRANCH    CHORDATA 


The  trogons  (fifty  species)  are  brilliantly  colored  tropical  birds.  The 
coppery  tailed  trogon  of  Texas  is  our  representative.  It  is  said  to  be  the 
most  beautiful  of  North  American  birds. 

Cuckoos  (two  hundred  species)  are  tropical  birds  represented  in  the 
United  States  by  several  species.  The  rain  crow,  or  yellow-billed  cuckoo 
(Fig.  244),  is  an  example.  It  feeds  on  the  tent  caterpillar  whicli  inlVst.s 
our  trees.  It  is  the  Old  World  cuckoo  which  lays  its  eggs  in  the  msts  of 
other  birds,  not  our  American  bird.  With  the  species  Ariis,  one  nest  serves 
for  several  females  and  it  sometimes  contains'  thirty  eggs.  The  joint  owners 
share  in  the  care  of  the  young. 


Fig.  244. — Yellow-billed  cuckoo  which  feeds  upon  hairy  tent  caterpillars. 
(After  Brehm.) 


Order  XV.  Pi'ci. — In  our  latitude  this  order  includes  wood- 
peckers of  various  kinds  and  under  various  common  names,  such 
as  red-headed  and  downy  woodpeckers  (Fig.  245),  sap-su(!kers, 
and  flickers  or  yellow-hammers.  All  are  arboreal,  and  all, 
except  the  sap-suckers,  are  insectivorous.  Their  toes  are 
arranged  two  in  front  and  two  behind,  except  in  a  few 
American  three-toed  woodpeckers.  The  tail  feathers  are 
stiff  and  help  to  brace  the  bird  as  it  clings  to  the  trunk  of 
a  tree  and  ])ecks  for  food.  The  l)ill  is  strong  and  fitted  for 
drilling  holes  into  trees  for  nests  or  to  procure  food.  The 
tongue  is  long,  flexible,  and  spear-tipped,  so  as  to  enable  the  bird 


LAND    BIRDS 


290 


to  reach  a  long  distance  and  to  spear  the  larvae  of  insects, 
on  which  it  delights  to  feed.  The  birds  of  this  order  are  poor 
singers,  but  good  drummers.  Everyone  has  heard  the  tattoo  of 
the  woodpecker  on  the  trunk  of  an  old  dead  tree.  The  four  to 
nine  eggs  are  white,  and  the  nest  is  placed  in  a  hole  high  up  in 
the  tree  away  from  enemies.  The  young  are  naked  and  are 
reared  in  the  nest  (altrioial).     There  are  350  species  distributed 


Fig.    245. — The    hairy    woodpecker    at    breakfast. 
U.  S.  Dept.  of  Agriculture.) 


(Biological    Survey, 


throughout  the  wooded  districts  of  the  world,  except  in  Madagas- 
car and  Australia.  The  North  American  species  are  not  highly 
migratory,  but  are  represented  in  the  northern  parts  of  their 
range  throughout  the  year,  since  they  feed  largely  on  the  eggs  and 
larvae  of  boring  insects,  which  they  can  find  all  the  year.  They 
are  of  great  value.  Two-thirds  or  more  of  the  food  of  the  downy 
and  hairy  woodpeckers  consists  of  noxious  insects. 


300  BRANCH    CHORDATA 

Order  XVI.  Machrochi'res. — To  this  order  belongs  a  group  of 
remarkable  flyers,  such  as  the  humming-bird,  chimney-swifts, 
whip-poor-wills,  and  night-hawks.  These  birds  have  long, 
pointed  wings.  Most  of  them  fly  at  dusk  or  at  night  and  .^eed 
chiefly  on  insects. 

The  humming-birds  are  tropical  or  semitropical  birds  of  the  New  World, 
there  being  .some  400  or  .500  species.  The  hawk  or  sphynx-moths  which 
feed  at  dusk  may  be  mistaken  for  humming-birds.  Apgar  says  several 
species  are  found  west  of  the  Rocky  Mountains  in  the  United  States.  The 
ruby  throated  humming-bird  is  the  one  we  see  about  our  trumpet-creepers, 
honeysuckle,  and  salvia,  seeking  both  insects  and  nectar.  Chapman  says 
"  the  young  are  fed  by  regurgitation,  the  parent  bird  inserting  its  bill 
into  the  mouth  of  its  offspring  and  injecting  food  as  though  from  a  syringe." 
Its  note  is  a  mere  squeak  or  prolonged  twitter.  A  humming-bird's  nest  is 
about  the  size  of  a  lady's  watch,  and  the  two  frail,  pearly  white  eggs,  like 
large  peas,  hatch  in  fourteen  days. 

The  swifts  are  widely  distributed.  They  have  strong  wings.  They  can 
fly  straight  up  or  down  and  feed  on  the  wing.  The  legs  are  so  weak  that 
some  species  cling  to  a  vertical  surface,  using  the  tail  to  help  support  them, 
instead  of  perching.  The  tip  of  each  tail  feather  ends  in  a  sharp  point, 
the  shaft  extending  beyond  the  vane.  They  nest  in  hollow  trees  or  chim- 
neys. "  The  nest  of  our  chimney-swift  is  a  bracket-like  basket  of  small 
twigs  gathered  while  the  bird  is  on  the  wing,  and  glued  together  and  to  tree 
or  chimney  by  a  glutinous  saliva." 

The  night-hawk  resembles  the  whip-jjoor-will,  and  is  usually  compared 
with  it,  bul  it  is  a  bird  of  the  sky,  and  "  its  note  is  a  loud  nasal  peent  uttered 
as  it  flies."  It  has  an  enormous  mouth  fringed  above  with  bristles.  It 
eats  insects  which  it  catches  on  the  wing.  When  it  alights  it  chooses  a 
nearly  horizontal  limb  on  which  it  sits  lengthwise,  looking  like  a  big  knot. 
It  migrates  to  South  America  in  winter 

The  whip-poor-will  is  well  known  by  its  peculiar  cry.  It  feeds  on 
insects  which  it  catches  at  night  as  it  flies.  During  the  day  it  rests  quietly 
on  the  ground  in  the  woods. 

Order  XVII.  Pas'seres. — This  vast  order  comprises  at  least 
half  of  the  birds.  They  have  four  toes,  three  in  front  and  one 
behind,  on  a  level  with  the  front  toes.  The  legs  are  rather  slen- 
der, and  so  placed  on  the  body  as  to  give  it  a  horizontal  position 
when  it  rests.  These  are  our  most  common  birds.  They  vary 
in  size  from  the  little  house  wren  to  the  crow.  Thrushes,  blue- 
birds, kinglets,  chickadees,  creepers,  wrens,  wag-tails,  warblers, 
vireos,  shrikes,  wax-wings,  swallows,  tanagers,  sparrows,  orioles, 
crows,  larks,  and  fly-catchers  are  representatives  of  this  order. 
They  include  some  of  our  finest  songsters.  Most  of  them  are 
plainly  clad,  inconspicuous  birds,  working  and  singing,  often 
unseen.     Not  all  of  them,  however,   are  unattractive  in   ap- 


LAND    BIRDS  301 

pearance,  for  think  of  the  boboHnk,  the  magpie,  the  jay,  the 
grosbeak,  the  tanager,  the  cardinal,  the  oriole,  and  the  modest 
little  wax-wing.  Each  brings  to  one's  mind  a  different  type  of 
beauty.  The  temperate  zone  contains  the  sweetest  singers  in  all 
the  bird  world.  The  great  majority  of  this  order  live  upon  insect 
food,  wherein  lies  their  greatest  value.  Others  live  on  weed 
seeds  and  waste  grain,  and,  lastly,  on  fruit  in  its  season. 

The  fly-catchers  {Tyran'nidm)  (Fig.  246)  are  found  only  in  America, 
being  especially  abundant  in  the  tropics.     They  number  over  350  species. 


Fig.  246.— Phoebe.     (Bulletin  17,  U.  S.  Biological  Survey,  1902.) 

Of  the  thirty  species  that  breed  here,  not  more  than  a  half  dozen  are 
permanent  residents  of  the  temperate  region.  They  feed  on  insects,  mostly 
injurious  ones,  which  they  catch  while  on  the  wing. 

The  true  larks  {Alau'dida;)  are  chiefly  Old  World  birds,  there  being  about 
100  species  in  Europe,  most  notably  the  skylark.  We  have  only  about  a 
dozen  of  this  family,  the  horned  and  shore  larks.  The  "  meadow-lark  " 
belongs  not  in  this  family,  but  with  the  blackbirds. 

Of  the  crows  and  jays  (Cor'vidcF)  we  have  about  twenty-five  of  the  two 
hundred  species.  They  are  migratory  only  to  a  certain  extent,  being 
winter  residents  except  in  the  North.  They  are  omnivorous,  eating  fruits, 
seeds,  insects,  and,  in  some  cases,  the  eggs  and  young  of  other  birds.  This 
last  habit  is  by  far  their  worst  one.     They  have  unusual  intelligence. 


302  BRANCH    CHORDATA 

The  orange  and  black  Baltimore  oriole  (Fig.  247),  one  of  the  most  beauti- 
ful, as  well  as  useful,  of  our  summer  birds,  destroys  many  tent  caterpillars 
and  other  hairy  larvaj  which  few  birds  will  eat.  If  one  has  ever  known 
his  rich,  clear  whistle,  one  can  never  forget  it  or  fail  to  recognize  it  when  the 
bird  arrives  about  the  first  week  of  May.  The  delicate  hanging  nest, 
which  the  female  weaves  of  grass  and  hair  and  strings,  is  a  marvelous  ac- 
complishment. It  is  suspended  far  out  near  the  end  of  a  small  flexible 
twig,  where  cats  and  boys  cannot  come.     The  elm  is  a  favorite  nesting  tree. 


1 


Fig.  247. — Baltimore  oriole  attacking  nest  of  American  tent  caterpillar. 
(Bulletin  75,  1900,  New  Hampshire  Coll.  Exp.  Station.) 

Grackles  or  blackbirds  are  common  summer  residents.  They  are  said 
to  have  the  same  batl  habit  as  the  jays  and  crows,  of  eating  the  eggs  and 
young  of  other  birds,  though  they  eat  also  many  injurious  insects. 

The  cowbird  lays  its  eggs  in  the  nests  of  other  birds.  It  should  be  killed 
and  its  eggs  destroyed. 

The  largest  family  {Frmgill'ida')  of  birds  (about  500  species),  containing 
the  finches,  sparrows,  and  grosbeaks,  is  represented  everywhere  except  in 
the  Australian  region.  They  are  chiefly  seed-eating  (Fig.  248)  and  so  are 
less  migratory  than  insect-eating  birds.  The  sparrows  are  plain-inhabiting 
and  are  protectively  colored,  while  the  more  arboreal  grosbeaks  and 
finches  are  rather  brilliant. 


LAND    BIRDS 


303 


Fig.  248. — Four  common  seed-destroying  sparrows:  1,  Junco;  2,  white- 
throated  sparrow;  3,  fox  sparrow;  4,  true  sparrow.  (Bulletin  17,  Biological 
Survey,  ,U.  S.  Dept.  of  Agriculture.) 


304 


BRANCH  CHORDATA 


Although  the  tanagers  are  ciistinctively  American,  only  five  of  them  come 
so  far  north  as  the  United  States.  They  are  remarkable  for  their  brilliant 
plumage.  When  one  sees  the  tanager  in  his  royal  or  "  court  costume  "  one 
feels  that  this  beautiful  bird  of  summer  has  indeed  put  brightness  into 
that  day.  Tanagers  are  arboreal,  loving  the  woods.  They  feed  on 
flowers,  fruit,  and  insects. 

Swallows  {Hi'rundin'ida:)  have  a  remarkable  power  of  flight.  In 
summer  they  are  found  throughout  North  America.  Our  barn  swallow  in 
winter  goes  as  far  south  as  Brazil.  The  number  of  injurious  and  annoying 
insects  which  they  catch  on  the  wing  is  almost  beyond  imagination. 

The  wax-wings  (Am pel' idee)  (Fig.  249)  are  found  in  the  northern  parts  of 
both  the  Old  and  New  Worlds,  though  there  are  but  three  species.  They 
feed  chiefly  on  wild  fruits  and  insects,  including  the  elm  beetle.     They  are 


C    ' 


Fig.  249. — Cedar  wax-wing.     (Biological  Survey,  U.  S.  Dept.  Agricul.) 


usually  found  in  small  flocks.  Their  common  notes  are  a  few  unmusical 
calls,  which  our  cedar  wax-wing  usually  utters  when  about  to  fly.'  The 
quiet  beauty  of  these  birds  is  beyond  all  description. 

The  warblers  {Mjiiotil'tidcp)  are  characteristic  North  American  birds 
and  number  more  than  100  species,  of  which  70  visit  the  United  States.  The 
others  are  tropical.  With  us  in  the  temperate  region  they  are  only  birds 
of  passage,  making  us  brief  but  regular  \isits  in  May  as  they  go  to  their 
northern  breeding  ground,  and  again  in  Sc])t('iiil)cr  as  they  return  to  the 
southland.  Most  of  them  are  woodland  l)inls.  Some  are  terrestrial,  some 
arboreal,  and  others  are  lovers  of  the  thickets.  They  migrate  by  night. 
Insects  constitute  nearly  their  entire  food,  and  they  are  among  our  best 
friends. 

*  Reed  and  Chapman. 


LAND    BIRDS 


305 


The  black-masked  Maryland  yellow  throat  is  one  of  the  tiny  warblers 
often  seen  in  the  Missi.syippi  Valley.  He  haunts  the  thicket.  His  song, 
"  witchery,  witchery,  witchery,"  is  characteristic  of  his  active,  nervous 
energy. 

The  little  black  and  white  warbler,  often  called  the  black  and  white 
creeper,  is  about  5  inches  long.  It  is  a  more  active  climber  than  even  the 
true  creepers,  hanging  from  the  under  surface  of  branches  and  twigs  or 
flitting  from  tree  to  tree.  It  is  usually  silent.  Its  occasional  "  see-see-see  " 
is  thin  and  wiry. 

The  wrens,  thrashers,  and  the  mocking-bird  (Fig.  250)  {Troglodyt'idce) 
include  many  hne  singers.  They  are  inconspicuously  colored  birds,  feed- 
ing near  the  ground.  Many  of  them  like  the  low  scrubby  tangled  growth 
so  dear  to  the  catbird,  which  cheers  us  all  the  summer  day,  rain  or  shine. 
.This  bird  does  valiant  service  as  a  caterpillar  hunter,  especially  when 
feeding  the  young. 


Fig.  250. — Mocking-bird.     (Biological  Survey,  U.  S.  Dept.  Agricul.) 

The  creepers  (CcrthiHdce)  do  good  work  in  keeping  down  the  pests  of  the 
tree  trunks  all  th(>  year  around. 

The  nuthatches  (Par'idcr)  also  help  in  tree  keeping,  as  do  our  little  chick- 
adees, which  stay  the  winter  through. 

The  thrushes  ( Tur'iUil(r)  arc  usually  fine  singers.  The  best  known  are 
the  much-loved  r()l)in  and  l)lucbird  (Fig.  251). 

Ther(>  are  several  otluT  families  of  Passeres,  but  lack  of  space  forbids  us 
to  dwell  longer  on  this  fascinating  subject. 


Economic  Importance. — Millions  of  dollars'  worth  of  farm 
products  are  destroyed  annually  by  insect  pests,  but  if  these  great 
hordes  of  marauders  were  not  held  in  check  by  their  natural 
enemies,  the  birds,  the  devastation  would  be  so  great  in  a  few 
years  as  to  cause  actual  famine. 

20 


306 


BRANCH  CHORDATA 


Where  man  has  not  interfered,  nature  has  a  well-balanced 
arrangement  for  the  protection  of  his  crops.  The  grasses  and 
low-growing  herbs  are  protected  from  such  enemies  as  the  cut- 
worm, caterpillar,  and  grasshopper  by  the  chipping  sparrow, 
robin,  and  bluebird,  and,  farther  afield,  by  the  quail,  meadow- 
lark,  blackbird,  and  field  sparrow.     In  the  edge  of  the  woods  are 


Fig.  251. — Bluebird  at  edge  of  nest  with  grasshopper  in  mouth.  (From 
photograph  by  Rev.  P.  B.  Peabody.)  (Bulletin  17,  Biological  Survey, 
U.  S.  Dept.  of  Agriculture.) 


the  chewinks  and  brown  thrashers;  and  in  the  deep  woods,  the 
ruffed  grouse ;  while  along  the  fresh-water  streams  and  ponds  may 
be  seen  the  woodcocks,  sandpipers,  and  snipes.  In  the  trees 
"the  woodpeckers,  assisted  by  the  nuthatches  and  creepers, 
look  after  insects  on  and  beneath  the  bark  of  both  the  trunk  and 
the  branches. ""^     The  chickadees,  bluebirds,  thrushes,  warblers, 

1  Weed  and  Dearborn,  "  Birds  in  Their  Relation  to  Man.'"' 


LAND    BIRDS 


307 


vireos,  kinglets,  and  many  more  guard  the  leaves.  The  insects 
of  the  air  are  preyed  upon  in  the  daytime  by  the  diurnal  birds, 
such  as  the  swallows,  swifts,  kingbirds,  and  fly-catchers.  Cre- 
puscular insects  are  caught  by  such  birds  as  the  whip-poor- 
will,  night-hawk,  and  small  owls. 

Hawks  and  owls  destroy  many  rats  and  mice  and  other  young 
rodents,  while  the  vultures  are  very  useful  as  scavangers,  since 
they  subsist  largely  on  carrion.  The  South  African  secretary 
bird  (Fig.  252)  belongs  in  the  list  of  friends. 


Fig.    252. — Secretary  bird   (Uypogcr'anus  reptiUv'orus).     A  South  African 
snake-killer  protected  by  law.     (After  Houssay.) 


Certain  kinds  of  birds  are  of  especially  great  value  on  account 
of  their  specific  food,  insect  pests  which  are  making  such  havoc 
with  particular  crops  or  with  certain  trees.  Thus,  the  swallows, 
which  eat  almost  nothing  of  value  to  man,  prey  upon  the  cotton- 
boll  weevil,  which  they  catch  upon  the  wing.  Forty-seven  adult 
weevils  have  been  found  in  the  stomach  of  a  single  swallow.  It 
should  be  remembered  that  the  swallows,  which  are  such  inde- 
fatigable insect  destroyers  here  in  the  breeding  season,  migrate 


308 


BRANCH  CHORDATA 


to  the  South  and  are  of  great  specific  value  there  by  reason  of  their 
raids  upon  the  cotton-boll  weevil,  so  they  should  be  encouraged 
and  protected  from  the  English 
sparrow.  Orioles  do  royal  service 
in  catching  weevils  on  the  bolls. 
Blackbirds,  wrens,  and  fly-catchers 
do  good  work. 

Sparrows  prey  upon  the  green 
wheat  aphid  of  North  Carolina. 

During  an  outbreak  of  canker- 
worm  in  a  central  Illinois  apple 
orchard  the  investigations  of  Prof. 
S.  A.  Forbes  showed  that  the  food 
of  robins,  catbirds,  brown  thrashers, 
and  bluebirds  consisted  of  96  per 
cent,  insects,  of  which  16  per  cent, 
was  cankerworms,  while  the  food  of 
the  house  wrens  he  examined  was 
50  per  cent,  cankerworms;  25  per 
cent,  of  the  food  of  the  hairy  and 
downy  woodpeckers  consists  of  bor- 
ing larvse. 

It  is  true  that  birds  eat  a  certain 
percentage  of  fruit  and  seeds,  but 
the  entire  amount  of  vegetable 
matter  is  usually  much  less  than 
the  animal  matter  consumed.  A 
large  proportion  of  the  seeds  eaten 
are  weed  seeds  (Fig.  253),  such  as 
dandelion,  dock,  knot-weed,  purs- 
lane, pigeon-grass,  and  rag-weed.^ 
The  grain  which  birds  eat  is,  much 
of  it,  picked  up  from  the  waste 
matter  about  the  farm-yard. 
Doctor  Judd^  says  the  great  horned  owl,  the  sharp-shinned 
and  Cooper  hawk,  and  the  English  sparrow  are  injurious  birds 


Fig.  253.— Weed  seeds 
commonly  eaten  by  birds: 
a,  Birdweed;  b,  lambs'  quar- 
ter; c,  purslane;  d,  amaranth; 
e,  spotted  spurge ;  /,  ragweed ; 
g,  pigeon  grass;  h,  dandelion. 
(Biological  Survey,  U.  S. 
Dept.  Agricul.) 


'Jackson  and   Daugherty,    "Agriculture  through  the  Laboratory  and 
School  Garden." 

2  Linville  and  Kelly. 


LAND    BIRDS  309 

and  should  be  killed.  The  cowbird  should  be  added  to  this  list, 
since  it  lays  its  eggs  in  the  nests  of  smaller  birds.  When  this 
hatches,  it  deprives  their  young  of  room  and  care,  often  pushing 
them  out  of  the  nest,  or  taking  their  food  and  allowing  them  to 
starve.  The  blackbirds  and  jaybirds  are  questionable  charac- 
ters, since  they  are  so  mean  about  robbing  nests  and  driving 
away  other  birds.  The  protection  of  all  but  the  few  birds  named 
should  be  emphasized,  especially  by  all  farmers  and  fruit  growers. 

The  useless  destruction  of  bird  life  every  year  is  alarming. 
Besides  the  thousands  on  thousands  killed  for  food,  there  are 
thousands  of  others  killed  l^y  the  plume-hunters  to  gratify  the 
foolish  pride  of  thoughtless,  silly  women.  Much  as  this  is  to  be 
deprecated,  it  slaughters  but  one-fifth  as  many  birds  as  those 
killed  by  men  and  boys  for  the  mere  sport  of  killing.  Surely 
the  killing  for  the  love  of  it,  many  times  leaving  the  birds  to 
decay  where  they  have  been  shot,  perhaps  only  wounded  and 
left  to  die  by  a  slow  torture  of  starvation,  is  a  cruel  and  sense- 
less practice,  yet  fully  one-half  of  all  the  birds  killed  in  the  United 
States  are  killed  merely  for  sport.^ 

Surely  it  is  time  to  stop  and  think;  time  to  teach  the  coming 
generation  the  value  of  birds  to  human  life;  time  to  teach  the 
boys  and  girls  to  love  the  birds  and  to  study  their  habits,  so  as  to 
learn  which  are  friends  and  which  foes.  Girls  should  learn  that 
a  dead  bird  upon  the  hat,  no  matter  how  beautiful,  is  a  mark  of 
the  heartlessness  of  the  wearer.  Boys  should  be  taught  to  shoot 
birds  with  a  camera,  not  with  a  gun.  It  takes  far  more  intelli- 
gence and  skill  and  will  be  found  a  more  fascinating  sport. 

Laws  are  being  made  in  many  states  for  bird  protection.  The 
United  States  Government  is  making  bird  reservations,  such  as 
Pelican  Island,  off  the  coast  of  Florida;  Breton  Island,  Louisiana; 
Stump  Lake,  North  Dakota,  and  Yellowstone  Lake  in  the 
National  Park. 

Geographic  Distribution. — Birds  as  a  class  are  the  most 
widely  distributed  of  all  animals.  They  are  at  home  in  the 
frozen  regions  of  the  North  or  in  the  dense  shades  of  the  tropics, 
upon  the  rocky  steeps  of  the  mountains,  or  out  on  the  ocean  far 
from  sight  of  land.  Their  wide  range  of  variation  in  structure 
and  habits  renders  them,  as  a  class,  able  to  adapt  themselves  to 
1  Hornaday,  p.  172. 


310 


BRANCH    CHORD ATA 


all  climates,  and  their  mode  of  locomotion  makes  them  less  re- 
stricted l)y  barriers. 

Important  Biologic  Facts. — Birds  have,  in  common  with 
reptiles,  the  quadrate  bone,  and  but  one  occipital  condyle. 
They  are  wonderfully  adapted  to  their  aerial  mode  of  life  by 
their  feathers,  by  the  modifications  of  the  fore  limbs  into  wings, 
and  by  the  air-filled  cavity  of  the  bones.  Birds  are  warm- 
blooded (homoiothermal) ,  the  heart  being  completely  divided 
into  right  and  left  halves.  The  fusion  of  the  bones  of  the  hand 
and  the  tibiotarsus  and  the  tarsometatarsus  are  peculiar  to 
birds.  Nest  building,  as  well  as  incubation,  is  peculiar  to  this 
class,  though,  in  rare  instances,  fishes  build  nests  and  reptiles 
practice  incubation. 


Classification. 

Division 

A.  Rati'tse. 

B.  Carina'tse. 


Order 
Order 
Order 
Order 
Order 
Order 
Order 
Order 
Order 
Order 
Order 
Order 
Order 
Order 
Order 
Order 
Order 


I. 

II. 

III. 

IV. 

V. 

VI. 

VII. 

VIII. 

IX. 

X. 

XL 

XII. 

XIII. 

XIV. 

XV. 

XVI. 

XVII. 


Ostrich,  Rhea,  etc. 

Pygop'odes.       Grebes,  Auks,  and  Loons. 
Longipen'nes.    Gulls,  Terns. 
Tubina'res.        Albatross,  Petrel. 
Steganop'odes.  Cormorants,  Pelicans. 
An'seres.  Ducks,  Geese,  and  Swans. 

Odontoglos'sse.  Flamingoes. 
Hero'diones.      Herons,  Storks,  Ibises. 
Paludic'olse.       Cranes,  Rails. 
Limic'olse.  Snipes,  Plovers. 

Quails,  Grouse,  and  Chickens. 

Doves,  Pigeons. 

Hawks,  Owls. 

Parrots. 

Cuckoos,  Kingfishers. 

Woodpeckers. 

Swifts,  Humming-birds. 

All  our  most  common  small 


Galli'nse. 

Colum'bae. 

Rapto'res. 

Psit'taci. 

Coc'cyges. 

Pi'ci. 

Macrochi'res. 

Pas'seres 

(Perching  birds),  birds. 


MAMMALIA  311 


CLASS  VI.     MAMMALIA 


Mammals  are  homoiothermal,  bilaterally  symmetric,  air- 
breathing,  usually  hairy  chordates.  They  are,  as  a  rule, 
viviparous  and  suckle  their  young.  They  vary  in  size  from  the 
tiny  little  harvest  mouse,  probably  less  than  5  inches  long,  to 
the  great  sulphur  whale,  weighing  many  tons.  Not  all  of  them, 
however,  are  widely  distributed,  but  everywhere,  save  in  a  few 
of  the  South  Sea  Islands,  some  of  the  several  thousand  species 
are  found. 

Covering. — No  other  characteristic  is  more  rightfully  called 
a  distinguishing  characteristic  than  the  hair  of  mammals. 
True  hair  is  found  on  no  other  vertebrate.  It  is  general  to  find 
a  hairy  covering  among  mammals.  Even  among  the  Cetacea 
hairs  are  sometimes  found  upon  the  muzzle,  and  traces  of  hair 
are  sometimes  found  in  the  embryo.  The  skin  of  the  whale  is 
underlaid  by  a  layer  of  fat  or  blubber,  while  that  of  those  un- 
gulates that  are  sparsely  covered  with  hair,  as  the  rhinoceros, 
is  very  thick.  The  hair  may  differ  greatly  both  in  length  and 
texture.  It  may  be  soft  and  kinky  ''wool"  or  very  fine  fur. 
The  coarse  hairs  may  become  long,  hard  bristles,  like  those  of 
the  hog,  or  be  differentiated  into  stiff  "  spines,"  like  those  of 
the  porcupine,  or  into  a  scale  armor,  like  that  of  the  armadillo. 

Sweat  glands  in  the  skin  are  also  characteristic  of  mammals. 

The  skeleton  is  the  most  nearly  perfect  of  any  of  the  chordates. 
The  skull  (Fig.  254)  is  composed  of  fewer  bones  more  firmly 
united  than  in  the  lower  chordates.  The  lower  jaw  is  composed 
of  a  single  bone  on  each  side,  the  dentary,  and  is  articulated 
directly  with  the  squamosal.  The  skull  is  connected  with  the 
first  vertebra,  the  atlas,  by  two  occipital  condyles  instead  of  one, 
as  in  the  birds  and  reptiles. 

The  spinal  column  (Fig.  255)  consists  of  a  varying  number  of 
vertebrse,  the  first  two,  the  atlas  and  axis,  being  somewhat  modi- 
fied to  support  the  head  and  to  permit  its  various  movements. 
The  vertebrae  do  not  articulate  with  one  another  by  cup  and 
ball  (except  in  some  ungulates),  as  in  amphibians,  reptiles,  and 
birds,  since  the  intervertebral  disks  of  filjrocartilage  permit 
lateral  bending  of  the  spine.  The  vertebrae  are  classified,  ac- 
cording to  their  location,  as  cervical,  dorsal,  lumbar,  sacral, 


312 


BRANCH  CHORDATA 


and  caudal.  The  cervical  or  neck  vertebrae  are  nearly  always 
seven  (there  are  six  in  the  manatee,  and  six,  eight,  or  nine  in 
some  of  the  sloths) .  So  the  length  of  the  neck  depends  upon  the 
length,  not  the  number,  of  the  vertebrae.  The  dorsal  vertebrae 
carry  ribs  and  vary  in  number  (from  nine  in  Hypero' odon}  to 


MT  ET  No. 


Fig.  254. — Skull  of  a  dog,  side  view,  with  the  right  half  of  the  mandible 
or  lower  jaw  and  hyoid  arch,  the  lower  jaw  displaced  downward  to  show 
its  whole  form.  (Reduced).  a«,  Anterior  narial  aperture;  Af  7",  maxillo- 
turbinal  bone;  ET,  ethmoturbinal;  Na,  nasal;  ME,  ossified  portion  of  the 
mesethmoid;  CE,  cribriform  plate  of  the  ethmoturbinal;  Fr,  frontal; 
Pa,  parietal;  IP,  interparietal;  SO,  supra-occipital;  ExO,  exoccipital; 
BO,  basi-occipital;  /'.  / ,  iieriotie;  BS,  basisphenoid ;  Pt,  pterygoid;  AS, 
alisphenoid;  OS,  orhitospliennid;  PS,  presphenoid;  PI,  palatine;  Vo, 
vomer;  Mx,  maxilla;  PMx,  i)reiiKixilla  (.s/i,  stylohyal;  eh,  epihyal;  ch,  cera- 
tohyal;  hh,  basihyal;  th,  thyroh^ali  equal  the  right  half  of  the  hyoidean 
apparatus;  s,  symphysis  of  the  mandible;  rp,  coronoid  process;  cd,  condyle; 
a,  angle;  id,  inferior  dental  canal;  *,  the  part  of  the  cranium  to  which  the 
condyle  is  articulated.      (After  Tenney.) 


twenty-two  in  Hyrax).  The  lumbar  vertebrae  also  vary  in 
number,  usually  inversely,  as  the  dorsal,  their  sum  being  rather 
constant.  The  sacral  vertebrae  are  fused  together.  They  are 
absent  in  Ceta'cea  and  Sire'nia,  where  there  are  no  functional 
hind  limbs.  The  caudal  vertebrae  vary  from  three  to  fifty. 
^  Beddard's  "  Mammalia,"  p.  23. 


Mammalia 


313 


Fig.  255. — Skull  and  spinal  col- 
umn and  single  vertebra  of  a  com- 
mon cotton-tail  rabbit  {Le'pufi  syl- 
vat'icus) .  (Cleaned  and  mounted  by 
students.) 


Fig.  256.- 
bit. 


-Pelvic  girdle  of  Jack-rab- 
(From  dissection.) 


All  mammals  have  ribs.     They  vary  in  number  in  different 
groups,  or,  it  may  be,  in  different  species.     The  greater  number 


314 


BRANCH  CHOKDATA 


of  them  are  attached  anteriorly  to  the  sternum,  which  is  always 
present,  and  posteriorly  to  the  vertebrae,  but  there  are  also  a 
number  of  floating  ribs  or  those  attached  posteriorly  only. 

The  pectoral  girdle  consists  of  two  bones  on  each  side,  the 
scapula  (Fig.  257)  and  the  clavicle.  The  clavicle  is  absent 
in  ungulates,  which  use  their  fore  limbs  mainly  for  support  and 
in  walking,  but  it  is  well  developed  in  "  flying,"  digging,  or 
burrowing  mammals. 


Fig.  257. — Anterior  limb  of  man,  dog,  hog,  sheep,  and  horse:  .SV,  Shoulder- 
blade;  c,  coracoid;  a,  b,  bones  of  forearm;  5,  bones  of  the  wrist;  6,  bones  of 
the  hand;  7,  bones  of  the  fingers.  (Le  Conte's  "Geology,"  American 
Book  Co.,  Publishers.) 

The  pelvic  girdle  (Fig.  25G)  consists,  normally,  of  the  os  in- 
nominatum  on  each  side.  There  are  "four  distinct  elements  in 
each  one:  the  ischium,  the  ilium,  the  pubis,  and  the  cotyloid."' 

The  limbs  which  raise  the  body  from  the  ground  and  are  the 
principal  organs  of  locomotion  are  four  in  number,  except  in 
Sire'nia  and  Cetacea,  where  there  are  no  externally  visible  hind 
limbs.  Rudiments  of  the  pelvis  are  found  in  both  of  these  orders, 
and  in  some  of  the  Cetacea  rudiments  of  the  femur  and  of  the 
tibia.    The  bones  of  both  anterior  and  posterior  limbs  (Figs.  257, 

^  Beddard,  "  Mammalia,"  p.  41. 


315 


258)  vary  in  size,  shape,  and  number,  depending  on  the  en- 
vironmental habits.  In  all  but  the  Cetacea  the  ends  of  the  digits 
are  protected  by  horny  epidermal  coverings,  variously  termed 
hoofs,  nails,  or  claws.  Rudiments  of  these  are  found  in  the 
embryos  of  the  Cetacea ,  thus  suggesting  their  terrestrial  origin. 
The  Digestive  Organs. — One  of  the  peculiarities  of  the 
digestive  organs  in  mammals  is  the  development  of  the  salivary 
glands.  The  teeth  are  "heterodont"  (Fig.  254)  instead  of 
"homodont,"  as  in  some  of  the  lower   classes  of   chordates. 


Fig.  258. — Posterior  limb  of  man,  monkey,  dog,  sheep,  and  horse:  1,  Hip- 
joint;  2,  thighbone;  3,  knee-joint;  4,  bones  of  leg;  5,  ankle-joint;  6,  bones 
of  foot;  7,  bones  of  toes.  (Le  Conte's  "Geology,"  American  Book  Co., 
Publishers.) 

Some  mammals  have  no  teeth,  at  least  not  in  the  adult  stage. 
The  teeth  are  attached  to  the  premaxillary,  maxillary,  and  den- 
tary  bones,  and  to  no  others.  These  heterodont  teeth  may  be 
classed  as  incisors,  canines,  premolars,  and  molars.  The  teeth 
would  indicate  an  omnivorous  feeding  habit,  but  this  is  not  true 
for  all  mammals.  Some  are  omnivorous,  some  carnivorous,  and 
many  herbivorous.  The  teeth  often  give  a  hint  as  to  the  feed- 
ing habits,  as  well  as  proving  an  important  element  in  classifica- 
tion. 


316  BRANCH    CHORDATA 

The  mouth  is  generally  characterized  by  thick  and  fleshy  lips, 
which  serve  as  organs  of  prehension  to  grasp  the  food,  as  does 
also  the  tongue,  the  latter  being  also  the  seat  of  the  sense  of 
taste. 

Owing  also  to  the  varying  feeding  habits,  the  different  organs 
of  digestion  vary  in  size;  for  example,  the  intestine,  which  is 
longer  in  mammals  than  in  any  other  chordate,  is,  in  the  rumi- 
nants, ten  times  the  length  of  the  animal,  while  in  the  carnivora 
it  is  only  three  or  four  times  as  long.  At  the  junction  of  the 
small  with  the  large  intestine  there  is  a  blind  tube  or  cecum, 
which  is  especially  developed  in  most  of  the  vegetable  feeders. 

The  Circulatory  System. — The  '  heart  is  composed  of  four 
parts:  two  ventricles  and  two  auricles.  The  circulation  is 
double,  closed,  and  complete.  The  left  aortic  arch  is  present 
instead  of  the  right  aortic  arch,  as  in  birds.  "There  are  two 
features  in  the  venous  system  which  distinguish  all  mammals 
(except  Echidna)  from  the  lower  chordates.  The  hepatic  portal 
system  is  limited  to  a  vein  which  conveys  to  the  liver  blood 
derived  from  the  alimentary  tract;  in  no  mammal  (except  in 
Echidna)  is  there  any  representative  of  the  anterior  abdominal 
vein  of  the  lower  vertebrates.  ...  In  no  mammal  is  there  any 
trace  of  a  renal  portal  system.  The  kidneys  derive  their  blood 
from  the  renal  arteries  only."^ 

The  red  corpuscles  of  the  blood  of  mammals  differ  from  those 
of  other  chordates  in  being  much  smaller,  non-nucleated,  cir- 
cular, and  biconcave,  except  in  the  camel,  in  which  they  are 
elhptic. 

The  Respiratory  System. — No  mammals  have  external  gills, 
but  all  breathe  by  means  of  lungs  throughout  life.  Respiration 
is  aided  by  a  diaphragm  or  muscular  jiartition,  which  com- 
pletely divides  the  body  cavity,  separating  the  heart  and  lungs 
from  the  abdominal  viscera.  When  this  muscular  diaphragm 
contracts  its  upper  surface  becomes  more  concave,  increasing 
the  lung  cavity  and  allowing  the  lungs  to  expand  under  the  pres- 
sure of  the  air.  When  the  muscles  relax  the  upper  surface  again 
becomes  convex  and  the  lung  cavity  is  reduced,  thus  forcing  out 
the  air  of  the  lungs. 

The  soft  palate  and  the  epiglottis  are  structures  peculiar  to 
1  Beddard,  p.  88. 


MAMMALIA 


317 


mammals.     The  vocal  organs  are  in  the  upper  part  of  the  trachea 
instead  of  the  lower,  as  in  birds. 


Fig.  259. — a,  Brain  of  rabbit,  from  above;  the  roof  of  the  right  hemi- 
sphere is  removed  so  as  to  exjiose  the  lateral  ventricle;  }>,  the  same  from 
below;  c,  brain  of  cat;  on  the  right  side  the  lateral  and  posterior  part  of  the 
hemisphere  is  removed,  and  almost  as  much  on  the  left  side,  and  the  greater 
part  of  the  hemispheres  of  the  cerebellum  have  been  removed ;  d,  brain  of 
orang  (a,  b,  c,  after  Gegenbaur;  d,  from  the  regne  animal):  Vh,  Cerebral 
hemispheres;  Mh,  corpus  quadrigeminum;  Cb,  cerebellum;  Mo,  medulla 
oblongata;  Lo,  olfactory  lobe;  //,  optic  nerve;  F,  trigeminal;  VII,  VIII, 
facial  and  auditory  nerves;  H,  hypophosis  cerebri;  Th,  optic  thalamus; 
Sr,  sinus  rhomboidalis.     (After  Claus.) 


The    Nervous    System. — The   brain    is   relatively    larger   in 
mammals  than  in  other  chordates.     The  cerebral  hemispheres 


318 


BRANCH  CHORDATA 


are  especially  developed  and  are  connected  by  the  corpus  cal- 
losum,  which  is  not  present  in  birds.  The  brain  (Fig.  259),  with 
a  few  exceptions,  is  convoluted. 

The  special  senses  are  all  present  except  in  some  Cetacea, 
where  the  olfactory  membrane  is  degenerate  and  the  sense  of 
smell  is  lacking.  The  organs  of  sight  and  hearing  (Fig.  260) 
vary  most,  owing  to  the  different  environments  and  consequent 
habits  and  needs  of  the  various  species.  The  sense  of  touch, 
while  distributed  over  the  surface  of  the  body,  is  especially 


Fig.  260. — Diagram  of  the  labyrinth  of  the  ear  in  /,  the  fish;  //,  the  bird; 
and  ///,  a  mammal:  U,  Utriculus;  D,  sacculus;  US,  utriculus  and  sac- 
culus;  Cr,  canalis  reuniens;  R,  recessus  labyrinthi;  UC,  commencement  of 
the  cochlea,  C,  L,  lagena;  K,  cecal  sac  at  the  apex;  C,  cecal  sac  of  the  ves- 
tibulum  of  the  cochlear  canal.     (After  Waldeyer,  from  Gegenbaur.) 


sensitive  at  the  ends  of  the  fingers,  on  the  lips,  tongue  or  snout, 
and,  in  some  monkeys,  upon  the  under  surface  of  the  tail.  The 
cat  has  long  sensitive  hairs  (vihrissw)  connected  with  nerve-end- 
ings, which  are  tactile  in  function.  The  sense  of  taste,  situated 
on  the  base  and  tip  of  the  tongue  and  on  the  soft  palate,  is  more 
highly  developed  than  in  any  other  class. 

The  sense  of  scent  or  smell  is  highly  developed.  Correlated 
with  the  development  of  smell  is  the  presence  of  odoriferous 
glands  in  many  mammals.     The  odors  may  serve  for  recognition, 


MAMMALIA  319 

for  warning,  or  for  protection  by  mimicking  the  odors  of  a  more 
formidable  foe;  as  the  odor  of  the  musk  deer  may  suggest  that  of 
a  crocodile. 

It  is  readily  seen  that  the  nervous  system  is  the  highest  and 
most  complicated  of  any  chordate's,  thus  giving  mammals 
highest  rank  in  the  scale  of  intelligence. 

Order  I.  Monotrem'ata. — The  animals  of  this  order  are 
primitive  mammals,  but  that  they  are  mammals  is  proved  by 
the  fact  that  they  are  covered  with  hair  and  nourish  their  young 
with  milk.  The  heart  has  an  incomplete  auriculoventricular 
valve.  The  temperature  is  lower  and  more  variable  than  in 
the  higher  mammals.^  The  brain  has  no  corpus  callosum.  Like 
birds  and  reptiles,  they  are  oviparous,  and  the  intestines  open 
into  a  cloaca.     These  animals  are  characterized  by  a  temporary 


Fig.  261. — A  spill}'  ant-eater.     (From  Claus. ) 

"  mammary  pouch,"  in  which  they  are  hatched  or  to  which  they 
are  transferred  after  hatching,  and  into  which  open  the  ducts  of 
the  mammary  gland. 

The  spiny  ant-eater  {Echid'na  aculea'ta)  (Fig.  261)  is  a  small  nocturnal 
animal  about  the  size  of  a  duck-bill.  It  is  covered  with  spines  mingled 
with  hairs.  \Mien  danger  threatens  it  curls  up  like  a  hedge-hog.  Its 
legs  arc  sliort  and  stout,  and  its  feet  are  armed  with  strong  claws  for  tearing 
open  ant-hills.  Its  tail  is  vestigial.  It  has  a  long,  pointed,  toothless  snout 
and  a  long,  extensible  tongue  for  licking  up  ants,  other  insects,  and  worms. 
The  salivary  glands  are  very  highly  developed,  and  when  the  tongue,  cover- 
ered  with  sticky  saliva,  is  thrust  into  an  ant-hill,  it  is  soon  covered  with  the 
insects.  The  tongue  is  then  drawn  back  into  the  mouth  and  the  adhering 
insects  swallowed.  It  seems  that  the  mother  places  the  egg  in  the  mammary 
pouch  with  her  mouth.  When  the  young  is  hatched  it  is  nourished  with 
milk.  When  it  attains  sufficient  growth  she  removes  it  from  the  pouch,  re- 
placing it  from  time  to  time  for  nourishment.  She  shows  further  intelli- 
gence by  digging  a  burrow  and  concealing  her  young  in  it  when  she  goes  out 

'  Beddard,  p.  112. 


320 


BRANCH  CHORDATA 


at  night  for  food.     An  allied  form,  the  nodiak,  is  eaten  by  the  aborigines 
of  the  Papuan  region. 

The  duck-bill  {Ornithoryn'chm)  (Fig.  262)  is  found  in  southern  and 
eastern  Australia  and  Tasmania.  It  has  a  small,  round  head,  and  a 
broad,  flattened,  sensitive  bill.  Its  eyes  are  small  and  somewhat  hidden, 
but  well  developed.  Its  great  paddling  feet  are  five  toed  and  webbed,  the 
webs  of  the  anterior  feet  being  longer  than  the  claws.  It  is  about  the  size  of 
our  common  rabbit  and  has  short  legs  and  a  flattened  tail.  Its  body  is 
covered  with  loose  skin,  protected  by  thick,  glossy  hair,  with  an  under  layer 
of  fine  waterproof  fur.  The  duck-bill  is  aquatic,  digging  burrows  30  or  40 
feet  long  in  the  banks  of  streams.  One  opening  of  this  burrow  is  below  the 
water.  It  dives,  enters  this  opening,  and  is  safe  from  its  enemies.  It  has 
teeth  when  young,  but  soon  sheds  them,  and  the  gums  harden  into  horny 
plates  for  crushing  insects,  worms,  snails,  and  mussels,  which  it  digs  out  of 
the  mud  with  its  snout  and  stores  away  in  its  cheek  pouches  to  be  eaten  as 


Fig.  262. — Duck-bill  [Oni/ihurhyttchua  paradoxus).     (From  Liitken.) 

it  drifts  upon  the  water.  Sight  and  hearing  are  acute,  but  it  has  no  external 
ears.  The  male  is  armed  with  a  strong  horny  spur  on  each  hind  foot, 
which  is  connected  with  a  poison  gland.  The  duck-bill  is  as  shy  as  a  beaver. 
Its  voice  is  like  the  growl  of  a  puppy.     The  young  are  blind  and  naked. 


Order  II.  Marsupia'lia. — Marsupials  are  fur-covered,  terres- 
trial (rarely  aquatic),  or  arl)oreal,  or  subterranean  mammals, 
which  carry  the  young,  born  immature,  naked,  and  blind,  at- 
tached to  the  mammary  gland  in  an  abdominal  integumentary 
pouch.  The  milk  is  forced  down  the  throat  of  the  young  by 
the  muscular  action  of  the  mother.  The  young  are  able  to 
})reathe  at  the  same  time  by  the  wrapping  of  the  soft  palate 
around  the  upper  end  of  the  trachea  in  such  a  manner  that  the 
air  may  pass  from  the  nose  down  the  trachea  while  the  milk 
down  the  throat.     The  clavicle  is  present.     The  cloaca 


MAMMALIA 


321 


is  reduced.  The  corpus  callosum,  if  present,  is  rudimenatry. 
Parameles  possess  a  true  allantoic  placenta.  Many  thousand 
skins  of  the  opossums  are  used  yearly.  The  hair  is  used  in 
making  hats  and  felt.  The  fur  and  leather  of  the  kangaroo 
are  also  used. 

The  opossum  family  ( Didil' /ifufl(r)  consists  of  pendactylous,  plantigrade 
marsupials.  rii.>  pdii  'i  is  pi-  'sent  or  absent  according  to  the  species.  The 
great  loe  is  iaiv,.'  ai:(l  >>  paraM  •  trdiu  the  others,  making  the  foot  prehensile. 
The  tail  is  long,  |)rviK'n.sil.',  and  usually  covered  by  a  scaly  skin  and  a  few- 
scattered  hairs,  'there  are  two  distinct  genera.  The  first  has  been  divided 
into  several  by  some  authors. 


Fig.  263. — The  female  of  Didel'phys  dorsig'era,  one  of  the  South  American 
opossums,  carrying  its  young  upon  its  back.     (After  Nicholson.) 


Genus  Didelphys  comprises  twenty-three  species,  most  of  which  are 
tropical,  being  found  in  Mexico,  Central  America,  and  Brazil,  but  never  in 
Australia.  It  is  represented  in  the  United  Slates  by  the  common  opossum 
{Didd' phus  virgiind'na).  Its  habit  of  feigning  death  or  "playing  'possum  " 
when  confronted  by  an  enemy  is  well  known.  It  is  about  the  size  of  a 
large  cat.  Its  nose  is  pointed,  its  eyes  and  ears  large.  It  is  arboreal  and 
nocturnal.  It  eats  anything  from  insects  to  small  reptiles  and  birds,  and 
also  devours  muskmelons  and  certain  mushrooms;  indeed,  it  is  almost 
omnivorous.  It  does  not  hibernate.  Its  young  are  about  \  inch  in  length 
and  are  carried  in  the  pouch  for  about  eight  weeks.  After  this,  in  some 
species,  they  are  carried  on  the  back  (Fig.  263),  their  tails  interlocking 
with  that  of  the  mother. 

Tasmanian  marsupials  (family  Dasyur'idoe)  are  distinguished  from  the 
American  opossum  by  fewer  incisor  teeth,  a  rudimentary  first  digit  on  the 
fore  and  hind  feet,  by  the  absence  of  a  cecum,  and  by  a  non-prehensile  tail. 
21 


322  BRANCH    CHORDATA 

The  Tasmanian  wolf  has  a  skull  like  a  dog's,  and  is  like  the  ordinary  wolf 
in  size,  build,  and  habits.  It  is  of  a  dusky  hue  and  marked  upon  the  hind 
parts  with  blackish  bands.  The  hallux  is  wanting.  The  "Tasmanian 
devil  "  is  black  with  white  patches  on  the  body.  It  is  the  size  of  a  badger 
and  its  voice  is  a  yelling  growl. 

The  Australian  ant-eater  is  of  a  Isright  reddish  color,  banded  posteriorly 
and  dorsally  witli  white,  and  looks  much  like  a  large  red  squirrel.  It  feeds 
upon  ants,  wliicli  it  captures  with  its  tongue.  Its  habitat  is  both  terrestrial 
and  arboreal.  The  young  are  nourished  as  in  other  marsupials,  but  the 
pouch  is  lacking,  and  they  are  concealed  only  by  the  long  hair  of  the 
mother. 

The  Australian  mole  has  somewhat  the  appearance  and  habits  of  our 
common  mole.  It  is  pale  golden  red,  in  harmony  with  the  arid  soiHn  which 
it  lives.  The  claws  of  the  third  and  fourth  front  toes  are  enlarged.  "It 
is  not  only  blind,  but  its  eyes  have  been  more  completely  lost  by  degenera- 
tion than  in  any  other  known  case.  Its  anatomy  abounds  in  curious 
adaptations  to  an  underground  existence,  evidently  antique." 

The  Wombats. — There  are  three  species,  one  Tasmanian  and  two  Aus- 
tralian. Cheek  pouches  and  tail  are  rudimentary.  They  are  heavily 
built  animals,  like  the  badger  or  marmot,  with  a  shuffling  gait.  They  are 
gregarious,  live  in  burrows,  and  feed  upon  roots.  They  are  gentle,  but 
stupid.     Over  a  hundred  thousand  skins  are  sold  in  London  yearly. 

Several  of  the  smaller  species  of  family  Phalanger'idcE  are  called  "flying 
phalangers."  They  cannot  fly  upward,  of  course,  but  are  supported  by 
a  parachute-like  membrane  from  fore  to  hind  limb,  as  they  descend  with  a 
sort  of  skinuniiig  or  sailing  movement.  The  tail  is  usually  long  and  pre- 
hensile, and  tlic  thumb  opposable  and  nailless. 

The  Kangaroos  {Mncropod'idce)  are  herbivorous  marsupials  of  Australia 
and  the  surrounding  islands  (Fig.  264).  They  have  three  incisors  on  each 
side  of  the  upper  jaw  and  one  on  each  side  of  the  lower.  The  lower  pair 
of  incisors  are  sharp  on  the  inner  edge,  and  to  some  extent  may  be  moved 
toward  and  from  each  other,  cutting  grass  like  shears.  The  fourth  toe  of 
the  hind  foot  is  exceedingly  long  and  strong,  and  the  fifth  nearly  as  strong, 
but  shorter,  while  the  third  digits  are  syndactylous,i  but  so  slender  that 
they  are  of  no  use  in  supporting  the  body.  The  fore  limbs  are  short  and 
small  and  are  used  only  for  grasping.  With  the  exception  of  Dendrol'agus, 
which  is  arboreal  and  has  less  difference  in  the  length  of  fore  and  hind  limbs, 
this  family  is  terrestrial.  Locomotion  consists  of  a  series  of  leaps,  effected 
by  the  long  limbs  and  the  long  and  powerful  tail.^  They  vary  in  size  from 
that  of  a  rabbit  to  giant  forms  5  or  6  feet  in  height.  The  larva^  of  a  large 
kangaroo  is  not  over  3  inches  in  length.  They  are  gregarious,  the  droves 
numbering  from  50  to  150.  They  are  crepuscular,  nocturnal,  and  herbiv- 
orous. They  are  timid,  shy,  and" harmless  if  unmolested,  but  they  can  rip 
open  a  dog  with  their  strong  hind  claw  when  necessary  to  defend  themselves. 
When  wounded  they  take  to  water,  and  if  they  get  hold  of  a  dog,  they  under- 
take to  drown  it. 

Genus  Mac'ropus  includes  kangaroos  and  wallabies,  making  together 
twenty-three   species.     Macropus   rufus   attains  the  height   of  5  feet,  5 

1  See  Glossary. 

2  Some  authorities  state  that  the  tail  is  not  used  in  rapid  locomotion, 
but  we  know  from  observation  of  the  kangaroo  in  the  Zoological  Gardens 
that  it  does  rest  upon  the  tail  between  successive  leaps  in  slow  locomotion. 

3  Refldard,  p.  124. 


MAMMALIA 


323 


inches,  not  including  the  tail.  M.  gigantius  is  reported  by  Sir  Josoiih  l^anks 
as  good  for  food.  It  is  said  that  a  large  kangaroo  in  rapid  flight  Icai)s  20  to 
30  feet  at  a  bound.  The  female  will  weigh  120  pounds,  some  old  males  weigh 
200  pounds.  The  smaller  species  of  kangaroos  furnish  the  most  fur  and 
leather  and  the  best  venison.  About  350,000  are  sold  in  London  annually. 
Rock  wallabies  (genus  Pelrog'ale)  have  a  shorter  claw  on  the  hind  foot 
and  a  more  .slender  tail,  which  is  thickly  covered  with  hair  and  never  used  in 
locomotion  (Fig.  264).     The  tail  is  used  as  a  balancer,  as  they  leap  from 


>^^ 


Fig   264.—Petrogale  xanthopus.     The  rock  wallaby,  with  young  in  pouch, 
(After  Vogt  and  Specht.) 

rock  to  rock.  They  are  found  in  Australia  only.  The  nocturnal  genus 
(Bettongia)  and  others  have  sometimes  been  inaccurately  called  "  rat 
kangaroos."  The  four  species  are  subterranean,  with  prehensile  tails, 
with  which  they  carry  their  food,  grass,  roots,  and  leaves.  One  species 
burrows  to  a  depth  of  10  feet.     It  is  found  in  Tasmania  and  Australia. 


Order  III.   Edenta'ta. — The  five  families  of  this  order  are 
arboreal,  terrestrial,  or  subterranean,  with  clawed  limbs.     They 


324  BRANCH    CHOKUATA 

are  chiefly  tropical.  The  name,  Edentata,  is  somewhat  mislead- 
ing, as  teeth  are  not  wholly  lacking,  except  in  the  family  Myrme- 
cophag'idce  and  the  African  genus  Manis,  which,  having  no  use 
for  teeth,  have  lost  them.  Front  teeth  are  always  lacking  in  this 
order.  None  of  the  teeth  in  the  adult  have  enamel.  They  are 
said  to  be  stupid  and  sluggish  creatures,  and,  except  in  the  ant- 
eaters,  the  brain  is  devoid  of  convolutions. 

Ant-eaters  (Mi/rmecophag'idce). — This  family  consists  of  three  South 
American  genera,  all  without  teeth  and  with  long  protrusible,  viscid  tongues, 
the  sali\-ary  glands  being  highly  developed.  The  snout  is  long  and  the  body 
covered  with  long  hair,  while  the  tail  is  long  and  bushy.  The  claws  are 
long  and  powerful,  enabling  them  to  tear  open  the  ant-hills,  or,  in  the  ar- 
boreal forms  {Taman'dua  and  Cydotu'rus),  to  tear  the  bark  from  trees  and 
search  for  insects  or  to  defend  themselves. 

The  great  ant-eater  (Myrmecophaga  jybata)  is  said  not  to  "fear  the 
presence  of  the  serpent's  fold  or  the  teeth  of  the  jaguar,"  and  will  rip 
open  a  big  dog  with  its  claws  before  the  dog's  teeth  can  make  an  impression 
through  the  shaggy  hair.  Including  the  tail,  this  species  may  reach  a 
length  of  6  or  7  feet.  The  tail  is  2  feet  long  and  said  to  be  the  largest  of 
that  of  any  mammal.  The  great  ant-eater  sleeps  through  the  day  in  a  kind 
of  "  lair  "  in  the  tall  grass,  where  it  lies  "  on  one  side  with  its  head  buried 
in  the  long  fur  of  the  chest,  the  legs  folded  together,  and  the  huge  tail 
curled  around  the  exposed  side  of  the  body.''^  They  are  numerous  in 
their  region,  although  the  mother  produces  but  one  each  year.  The  young 
stays  with  the  mother  a  year,  riding  on  her  back  when  little. 

The  sloths  {Brady pod' idee) ,  of  South  America,  are  arboreal  forms,  with 
very  long  anterior  limbs,  short  tails,  and  round  heads.  Instead  of  the  usual 
seven  cervical  vertebrae,  the  three-toed  sloth  ( Brad' y pus)  or  "  Ai,"  so  called 
from  its  plaintive  cry,  has  the  unusual  number  of  nine,  while  the  two-toed 
genus  (Choloe'pus)  has  the  exceptional  number  of  six.  The  toes  have  long, 
recurved,  non-retractile  claws  for  clinging  to  the  branches  of  trees.  The  feet 
are  like  hooks  with  the  fingers  bent  under  them,  hence  they  walk  slowly 
and  clumsily  on  the  ground,  but  climb  about  with  ease  in  the  trees,  where 
they  live  continually  day  and  night,  hanging  back  downward,  even  in  sleep, 
from  the  lower  side  of  the  limb.  They  never  descend  to  the  ground  unless 
compelled  to  do  so,  but  spring  from  tree  to  tree  in  search  of  food,  which  con- 
sists of  leaves  and  green  slioots.  They  are  nocturnal.  Their  hair  is  long 
and  shaggy  and  covered  with  minute  green  algff,  giving  the  animal  an  al- 
most perfect  resemblance  to  a  lichen-covered  branch.  This  may  be  taken 
as  an  example  of  commensalism  between  animals  and  plants. 

Armadillos  ( Dasi/pod'ida?). — There  are  several  genera  of  armadillos  (Fig, 
26.5),  and  they  arc  found  chiefly  in  South  America.  They  are  also  known 
in  Central  Aiiicrica,  and  one  species  is  said  to  occur  in  Texas.  They  are  the 
only  mammals  in  which  the  dermis  develops  into  hard  bony  plates  like  those 
of  the  turtle,  while  the  hair  on  the  dorsal  part  of  the  body  is  replaced  by 
horny  scales  covering  the  bony  plate. 

"  Traces  of  dermal  armature  exist  in  one  or  two  genera  of  the  whales.'''^ 

*  Ingersoll,  p.  471. 
2  Beddard,  p.  173. 


MAMMALIA 


325 


The  different  forms  are  distinguished  chiefly  by  the  number  of  the  movable 
bands  of  "scutes  "  between  the  anterior  and  posterior  shields.  The  little 
Chlamydoph'orus,  of  about  5  inches  in  length,  has  no  movable  bands  at  all, 
the  series  of  plates  being  uniform  and  continuous  even  to  the  neck.  The  con- 
spicuous external  ears  so  prevalent  among  the  armadillos  are  also  absent. 
Tolypeu'tes  can  roll  itself  up  into  a  ball  and  be  protected  by  its  armor,  or 
roll  away  from  its  enemies.  Its  walking  is  digitigrade  and  it  is  called 
"pig-footed."  Armadillos  are  omnivorous,  and  one  species  {Das'ypus 
sexcinc'tus)  is  especially  fond  of  carrion,  burrowing  up  to  a  carcass  like  bee- 
tles. The  limbs  of  armadillos  are  short,  powerful,  and  clawed,  enabling 
them  to  dig  rapidly  in  the  ground. 


Fig.  265. — Nine-banded  armadillo  (Das'ypun  novemcinc' tun) .     (Liitken.) 


Order  IV.  Sire'nia. — Those  are  dark-colored,  sparsely  haired 
or  l)ristly,  toothed,  herbivorous  mammals.  The  elongated 
snout  of  the  whale  is  replaced  l>y  large  movable  lips  for  grasping 
the  food,  which  consists  of  seaweed  and  other  aquatic  plants. 
External  ears  and  hind  limbs  are  absent.  The  anterior  limbs 
are  flipper-like,  but  more  flexible  than  those  of  the  whale,  and 
the  mother  sometimes  holds  the  young  under  her  arm.  The  tail 
is  horizontal.  Sirenia  grow  to  a  length  of  9  or  10  feet.  They 
have  two  sets  of  heterodont  teeth. 

The  dugong  (Fig.  266)  is  sparsely  covered  with  stout  hairs. 
The  thick  skin  is  underlaid  with  blubber.  It  is  found  on  the 
east  coast  of  Africa,  in  the  Indian  Ocean,  and  the  north  coast  of 
Australia,  and  in  the  Red  Sea. 

The  manatee  is  found  on  the  Atlantic  coast  of  South  America 
and  of  Africa,  and  in  the  mouths  of  the  large  rivers  of  these 
countries.  The  blubber  in  the  manatee  difl'ers  from  that  of  the 
whale  in  that  it  has  no  free  oil. 

Steller's  sea-cow,  the  recently  extinct'  Rhyti'na,  was  found  in 
herds  in  Behring  Sea.  It  reached  a  length  of  20  to  30  feet.  The 
flesh  was  good  for  food,  and  the  hide  and  oil  of  value. 

1  "About  1768  because  its  fearlessness  enabled  hunters  to  kill  it  easily." — 
Hegner. 


326 


BRANCH    CHORDATA 


Order  V.  Ceta'cea. — The  whales  must  be  regarded  as  true 
mammals,  since  they  nourish  their  young  with  milk.  Thej^  are, 
however,  hairless,  with  the  exception  of  a  small  number  of  hairs 
about  the  muzzle  in  some  species.  They  are  perfectly  acjuatic, 
never  leaving  the  water.  Their  form  is  fish-like,  with  a  large 
and  powerful  tail  horizontally  flattened,  with  a  fluke  on  each 
side.  The  tail  is  the  chief  organ  of  locomotion,  moving  up  and 
down  in  a  sort  of  rotary  motion,  and  thus  propelling  the  animal 
from  place  to  place. ^ 


'0h0fj, 


The  fore  limbs  are  fin-like  paddles  or  flippers  and  are  used  as 
balancers.  Whales  have  lost  all  external  trace  of  hind  limbs, 
but  a  pair  of  small  vestigial  bones  is  found  embedded  in  the 
body.     A  fleshy  dorsal  fin  is  generally  present. 

Whales  (Fig.  267)  are  distinguished  by  a  great  rounded  cra- 
nium, the  elongation  of  jaws  and  face,  and  by  a  prow-like  snout 
of  fat  for  the  defense  of  the  skull.  The  mouth  is  very  large  and 
the  throat  extremely  small.  The  nostrils  are  represented  by  a 
single  or  double  blow-hole  far  back  on  the  snout,  nearly  on  top 
of  the  head.  "  When  the  whale  breathes  the  expired  air  rushes 
out  through  the  nostrils.  The  vapor  in  this  expired  breath, 
1  Beddard,  p.  173. 


MAMMALIA 


327 


together  with  mucus  from  the  nostrils,  is  condensed  into  drops  of 
water  in  the  cold  regions,  but  the  water  taken  into  the  mouth 
does  not  pass  out  through  the  blow-hole.  The  nose  is  directly 
connected  with  the  windpipe,  so  that  a  whale  can  breathe  while 
swimming  through  the  water  with  its  mouth  open.  The  eyes 
are  relatively  very  small,  and  there  are  usually  no  external  ears." 
(Traces  of  external  ears  in  the  porpoise  are  recorded  l)y  Professor 
Howell.)^  The  opening  of  the  ear  is  minute.  The  cervical 
vertebrae  are  very  short  and  more  or  less  fused. 

The  skin  is  smooth  and  shiny,  like  coach  leather,  and  a  thick 
coating  of  fat  immetliately  underlies  the  skin.  The  blubber  or 
fat  from  whales  yielded  much  profit  from  its  oil  until  the  modern 


Fig.  267. — Skeleton  of  a  whalebone  whale,  and  section  of  the  mouth, 
with  whalebone:  6,  Blow-hole;  a,  upper  arm;  fa,  forearm;  h,  hand;  p,  th,  I, 
small  remains  of  pelvic  or  hip-bone,  thigh,  and  leg;  r,  roof  of  the  palate; 
w,  w,  plates  of  whalebone;/,  whalebone-fringe.  (Holder's  "Zoology," 
American  Book  Co.,  Publishers.) 

method  of  getting  oil  from  deep  oil  wells,  and  the  scarcity  of 
whales  has  almost  excluded  the  whale  industry  from  the  oil 
trade.  The  toothed  whales  feed  upon  fish  and  larger  marine 
animals,  while  the  whalebone  whales  feed  upon  minute  Mollusca, 
jelly-fish,  and  Crustacea. 

The  toothless  whales  are  those  in  which  the  teeth,  present  in 
the  embryo  only,  are  replaced  in  the  adult  by  baleen  or  whale- 
bone (Fig.  267),  a  horny  product  of  the  epithehum  of  the  mouth, 
which  consists  of  a  large  number  (from  330  to  370)  of  horny 
plates  hanging  down  like  curtains  in  pairs,  one  on  each  side  of 
the  mouth,  nearly  meeting  each  other  in  the  middle,  each  pair 
immediately  behind  another.  The  lower  edges  of  these  horny 
1  Beddard,  p.  346. 


328  BRANCH    CHORDATA 

plates  are  "  frayed  out "  and  form  a  strainer,  through  which  the 
water  taken  into  the  mouth  trickles  out,  leaving  the  small 
animals  from  the  water  in  the  mouth.  This  baleen  or  whalebone 
is  worth  several  dollars  a  pound,  and  from  800  pounds  to  several 
tons  are  derived  from  a  single  whale.  One  whale  has  been  re- 
ported as  furnishing  $12,230  worth  of  whalebone,  and  oil  valued 
at  $3490. 

Whales  vary  from  6  to  60  or  80  feet  in  length,  and  some  have 
been  found  100  feet  long.  The  voice  of  some  species  has  been 
described  as  similar  to  the  lowing  of  a  cow,  and  others  like  the 
bellowing  of  a  bull.     The  young  whale  is  called  a  calf. 


The  great  Ror'qual  whales  may  measure  from  60  to  85  or  even  100  feet. 
A  species  of  whale,  probably  of  genus  Balcenop' tera,  is  described  as  having  a 
mouth  so  wide  that  "divers  men  might  have  stood  up  in  it,  yet  the  throat 
so  narrow  as  would  not  lia\e  athnittcd  the  least  of  fishes.''  The  blue 
whale  (Balopnnp'kra  .sibbdl'dii)  is  tlie  giant  of  the  rorquals.  The  Califor- 
nia gray  whale  is  said  to  be  a  cunning,  courageous  enemy. 

The  "right  whales"  are  from  50  to  60  feet  long,  the  head  about  one- 
fourth  the  length  of  the  entire  animal,  and  with  no  dorsal  fins.  The 
whalebone  is  valuable  and  the  oil  is  of  excellent  quality  and  large  quantity. 
In  toothed  whales,  which  have  no  whalebone,  the  orifice  of  the  blow-hole  is 
single. 

The  sperm  whales  (Physeter'idoe)  have  teeth  in  the  lower  jaw  only.  Phy- 
se'ter  macroceph'alus)  is  from  55  to  80  feet  long.  The  head  is  enormous, 
ending  in  a  great  blunt  snout.  The  mouth  is  ventral  and  "  it  has  been  as- 
serted that  the  sperm  whale  turns  over  on  its  back  to  bite.''^  The  single 
blow-hole  is  not  in  the  median  line,  but  on  one  side.  Inside  of  the  great 
"  square  head  "  is  a  cavity  lying  above  the  skull,  which  during  life  is  filled 
with  oil  or  fluid  fat,  of  which  the  spermaceti  of  commerce  is  the  jn-oduct. 
This  oil  is  also  found  in  other  whales.  Ambergris,  an  exjx-nsivc  substance 
used  in  connection  with  perfumery  (which  is  at  first  a  greasy  mass  and  then 
hardens),  is  a  product  from  the  intestinal  canal  of  the  sperm  whale.  This 
whale  is  tropical.  The  females  are  found  in  herds  or  schools.  Their  food 
is  chiefly  cuttle-fishes.  The  throat  is  said  to  be  large  enough^  to  have 
swallowed  Jonah.  It  has  great  strength,  being  able  to  throw  itself  entirely 
out  of  the  water. 

Dolphins  and  porpoises  have  many  teeth  which  are  present  in  both  upper 
and  lower  jaw.  The  size  of  these  animals  is  small  to  medium.  The  Be- 
lu'ga,  or  "  white  whale,"  is  a  northern  species.  It  has  a  distinct  neck  and 
free  vertebne.  The  young  are  blackish,  growing  white  as  they  mature. 
This  porpoise  ascends  rivers  in  search  of  food,  which  is  preferably  salmon. 
One  {Deiphin'idce  elphineraptus)  is  fairly  common  in  the  Gulf  of  St.  Law- 
rence.^ 

1  Beddard,  p.  362. 

2  Ibid.,  p.  365. 

^  Shipley  and  McBride. 


MAMMALIA  329 

Distrihidion. — Cetacea  are  cosmopolitan,  mostly  marine.  A 
few  ascend  rivers,  some  being  exclusively  river  forms  of  South 
America  and  southeastern  Asia. 

Use  to  Man. — A  good  quality  of  ivory  is  obtained  from  nor- 
whal's  tusks  (the  left  upper  incisor  which  sometimes  reaches  a 
length  of  8  to  10  feet).  Whalebone,  oil,  and  spermaceti  have 
already  been  mentioned. 

Geologic  Distribution. — The  cetaceans  are  represented  in  the 
Eocene  and  Miocene  of  Europe,  Egypt,  and  North  America. 
Both  whalebone  whales  and  toothed  forms  have  been  found  in 
the  Pliocene  deposits.  The  toothed  whales  are  represented  in 
the  Miocene,  Pliocene,  and  Pleistocene  of  Europe,  North  Amer- 
ica, New  Zealand,  and  Australia  by  the  extinct  heterodont  family 
Squalodon'tidce. 

Order  VI.  Ungula'ta. — This  is  a  large  order  of  diverse  forms. 
A  large  proportion  of  these  forms  are  extinct,  and  existing  forms 
are  connected  to  some  extent  by  fossil  forms.  Many  of  these 
animals  are  very  large.  They  are  chiefly  herbivorous.  The 
molar  teeth  are  adapted  for  grinding  by  having  broad  crowns, 
with  tuberculated  or  ridged  surfaces.  Canines  are  absent  or 
small,  or,  in  a  few  cases,  tusk-like  in  the  upper  jaw.  Although 
the  older  types  were  plantigrade,  the  existing  forms,  excepting 
such  as  Hyrax,  are  digitigrade,  walking  on  the  tips  of  their 
toes.  The  one-four  terminal  phalanges  are  nearly  always  en- 
cased in  solid  horny  hoofs,  which  are,  in  reality,  enlarged  and 
thickened  claws.  The  weight  of  the  body  usually  rests  upon 
these  hoofs.  The  limbs  have  no  power  of  grasping  or  climbing, 
but  are  simply  organs  of  locomotion.  Clavicles  are  absent. 
This  is  the  only  order  of  mammals  in  which  horns  appear.  They 
are  surely  a  needed  and  effective  means  of  defense  in  those  forms 
which  are  too  heavy  to  be  swift,  as  they  cannot  defend  themselves 
with  teeth  nor  claws,  as  do  the  rodents  and  carnivores.  The 
order  contains  many  domesticated  animals  indispensable  to  man 
as  beasts  of  burden  or  as  food.  It  is  the  most  beneficial  to  man 
of  any  order  of  mammals. 

The  Hyrax  {Hyrac'ido'). — This  and  the  following  family  are  often 
placed  in  a  sub-order.  They  are  the  survivors  of  those  tiicat  nniinals  of 
the  past  that  had  their  wrist-bones  placed  in  a  loiifiit'idinal  scrir--  mikI  had 
toes  which  were  nearly  equal  in  length.     The  hyrax  (Fig.  'li\S)  is  a  small 


330  BRANCH    CHOUDATA 

animal  found  in  Ethiopia,  Africa,  and  Arabia,  including  Palestine.'  It 
is  sometimes  called  the  "rock-rabbit,"  since  the  most  species  live  among 
rocks  and  mountains,,  and  their  squatty  attitude,  short  tail,  and  split 
muffle,  as  well  as  a  pair  of  rodent-like  incisors  in  the  upper  jaw,  remind  one 
of  the  rabbit.  They  have  no  canine  teeth.  Some  species  are  found  upon 
the  trunks  and  large  branches  of  trees,  and  sleep  in  the  hollows  of  trees. 
The  skull  shows  affinity  with  the  Perissodactyles  and  afeo  with  the  rodents. 
The  ears  are  short  and  the  body  fur  covered.  The  clavicle  is  absent,  the 
radius  and  ulna  comi^lete,  but  often  ankylosed.  The  hyrax  has  a  greater 
number  of  trunk  vertebra;  than  any  other  mammal,  twenty-one  or  twenty- 
two  of  them  bearing  ribs.  The  hyrax  differs  from  all  other  mammals  in 
having,  in  addition  to  tlic  ordinary  cecum,  a  pair  of  supplementary  ceca 
situatrd  some  distance  down  the  large  intestine. 

The  Elephant  (  Eleplmn  'tidw). — The  skin  is  greatly  thickened  and  scantily 
coveretl  with  hair.  There  is  a  tuft  of  hair  on  the  end  of  the  tail.  The  mass- 
ive, stiff  limbs  are  quite  free  from  the  body.  The  nose  and  upper  lip^  are 
produced  into  a  long,  flexible,  muscular,  prehensile  trunk  or  proboscis  (Fig. 
269),  at  the  end  of  which  the  nares  are  situated.  There  are  five  complete 
digits  on  both  fore  and  hind  limbs,  and  though  they  are  bound  together  in 


Fig.  268. —  Hyrax  syriacus. 

the  integument,  each  is  encased  in  a  separate  hoof.  The  skull  is  very  large, 
but  the  bones  are  rendered  light  by  their  numerous  air  cavities.  The  brain- 
case  is  small  in  comparison  with  the  size  of  the  skull,  as  the  bones  are 
enormously  thickened.  In  some  specimens  the  bony  skull  wall  is  greater 
in  diameter  than  the  cranial  cavity,  the  frontal  bones  in  older  animals  some- 
times reaching  the  thickness  of  one  foot.  In  existing  forms  there  is  a 
single  pair  of  upper  incisors,  which  develop  into  long  tusks  of  solid  ivory. 
A  single  tusk  sold  in  London  in  1874  weighed  188  pounds.  There  is  no 
trace  of  any  canines.  Molars  are  so  large  that  there  is  never  but  a  single 
functional  one  on  each  side  of  each  jaw  at  a  time.  They  are  transversely 
ridged.     Elephants  are  herbivorous.     The  stomach  is  simple  and  the  cecum 

1  This  is  supposed  to  be  the  cony  of  the  Bible,  where  it  is  spoken  of  as  a 
"wise,  though  a  feeble  folk."  It  is  said  to  be  too  wise  to  be  caught 
in  traps,  at  least,  but  the  further  reference  that  it  "  cheweth  the  cud,  but 
divideth  not  the  hoof  "  throws  some  doubt  upon  its  identity.  However, 
Bruce  kept  one  in  captivitv  and  found  that  it  did  chew  the  cud.  (See 
Bcddard,  p.  234.) 

^Beddard's  "Mammalia." 


MAMMALIA 


331 


wide.  The  cerebral  hemispheres  are  much  convoluted,  but  the  cerebellum 
has  no  convolutions.  There  are  but  two  living  species:  one  {El'ephas 
africanus)  is  found  in  the  forests  of  tropical  Africa,  the  other  {E.  indicus) 
is  found  in  India,  Ceylon,  and  the  Malayan  Islands.  The  African  species 
has  not  the  two  rounded  bosses  which  give  the  wise  countenance  to  the 
Indian  species,  and  its  head  slopes  back  more  and  the  ears  are  much  larger. 
It  is  tligitigrade,  though  a  thick  pad  of  fat  makes  it  appear  plantigrade. 
It  reaches  the  height  of  about  12  feet.  "  Jumbo  "  was  1 1  fe(>t  to  the  shoul- 
der and  weighed  62  tons.  There  are  tusks  in  both  se.xes,  but  in  this  species 
they  are  larger  in  the  female.  The  tusks  are  used  not  only  as  a  means  of 
defense,  but  especially  the  right  one  is  used  also  for  grubbing  roots  for  food. 
The  Africa'nus  is  more  active  and  savage  than  In'dicus,  but  it  has  been 
tamed.  It  is  not  used  in  Africa  now  save  for  food  and  ivory.  It  is 
long  lived,  maturing  at  forty  and  living  one  hundred  and  fifty  or  more 


Fig.  269. — Various  uses  of  the  trunk  of  the  elephant:  1,  Drinking;  2, 
pulling  grass;  3,  washing.  (From  Holder's  "Elements  of  Zoology," 
American  Book  Co.,  Publishers.) 


years.  Elephas  indicus  is  invaluable  as  a  beast  of  burden  on  account 
of  its  great  strength,  though  not  all  are  to  be  depended  upon.  One  may 
be  perfectly  docile  and  obedient,  and  another  furious,  vicious,  and  un- 
manageable, but,  stranger  yet,  they  are  sometimes  exceedingly  timid. 
Baker  tells  of  one  he  was  riding  fairly  bolting  at  the  sight  of  a  hare.  The 
elephant  rushes  into  the  nearest  jungles,  when  bolting,  tearing  through 
the  underbrush,  while  the  rider  is  swept  off  or  torn  by  the  thorns.  Its 
obedience  to  the  slightest  sign  of  the  Indian  mahout  shows  that  it  has  con- 
siderable intelligence.  Baker  asserts  that  the  locality  and  time  of  ripening 
of  particular  kinds  of  fruit  are  remembered  by  it.  The  power  of  remember- 
ing and  recognizing  individuals  is  proved  by  their  revenge  of  particular 
treatment  of  certain  keepers.  This  group  of  ungulates  appeared  in  the 
Miocene. 

The  Mammoth  is  an  extinct  form  which  once  was  found  about  the  north 
pole  in  Siberia,  Europe,  and  America.     It  was  covered  with  long,  woolly  fur. 


332  BRANCH    CHORDATA 

Fossil  remains  of  another  extinct  form,  the  Maslotlon,  are  constantly  being 
found  in  the  gravel  pits  of  Europe,  Asia,  and  North  America.  Some  species 
have  tusks  in  both  jaws  and  tuberculated  niohirs  lik(;  the  pig. 


The  remainder  of  this  order  is  included  in  the  two  great  divis- 
ions of  Perissodac'tijla  (odd  toed)  and  Artiodac' tijla  (even  toed). 

Perissodactyla. — The  odd-toed  group  has  the  molars  and 
premolars  of  the  same  size  and  the  mitldle  toe  preflominantly 
developed.  "  The  other  toes  in  the  three  hving  families  are 
reduced  to  cUfferent  degrees." 

The  tapirs  ( Tapir'idce)  are  among  the  oldest  mammals  represented  to-day, 
the  family  being  as  old  as  that  of  Equidoe,  though  the  specialization  of  the 
toes  has  never  advanced  so  far.  The  fore  feet  are  four  toed,  and  the  hind 
feet  three  toed.  The  nose  and  the  upper  lip  are  lengthened  into  a  short 
proboscis. 

An  American  species  (Tnp'irus  terrestris)  is  a  solitary,  dull  and  gloomy, 
timid  and  defenseless  animal,  hiding  away  near  the  stream,  in  the  marshy, 
tropical  woods  in  the  daytime,  and  feeding  at  night.  \\'hen  alarmed  or 
pursued  it  always  takes  to  the  water  for  safety.  The  jaguar  is  its  most 
formidable  enemy. 

The  Malayan  forms  haunt  the  most  retired  spots  among  the  woofled 
hills,  thus  escaping  its  enemy,  the  tiger. 

The  tapirs  (genus  Tap'irus)  are  now  found  only  in  South  and  Central 
America,  the  Malay  Peninsula,  Java,  and  Sumatra.  They  are  small  or 
moderate  sized,  ungainly  creatures,  covered  with  brownish-black  hair. 
The  young  is  spotted  and  striped  with  white,  as  is  the  rule  among  quad- 
rupeds of  the  forest.^  The  tapir's  quick  senses  enable  it  to  slip  away, 
which  it  can  do  with  great  rapidity,  when  disturbed.  When  at  rest  in  the 
daytime  a  Malayan  form  "  exactly  resembles  a  grayish  boulder,  and  as  it 
often  lives  near  the  rocky  streams  of  the  hill  jungles,  it  is  not  easily  de- 
tected." Tapirs  are  browsers,  seizing  and  drawing  t  lie  succulent  leaves  and 
shoots  into  the  mouth  with  the  proboscis.  "  They  are  extremely  fond  of  the 
leaves  of  the  low-growing  cocoa  plant,  and  they  often  in  one  night  destroy 
a  cocoa  field  which  has  cost  a  poor  Indian  the  hard  labor  of  a  year." 

South  American  tapirs  are  said  to  make  interesting  pets.  They  are 
kept  in  the  National  Zoological  Park  at  Washington.  In  Costa  Rica  the 
tapir  is  much  hunted,  for  its  flesh  is  good,  both  fresh  and  salted,  and  its 
thick  hide  is  made  into  twisted  whips  (rawhides). 

The  primitive  forms  were  distributed  all  over  the  world,  "  but  as  the  later 
tertiary  conditions  changed  from  torrid  to  temperate  outside  the  tropics, 
they  became  extinct  everywhere  save  in  the  hot,  moist  climate  under  the 
equator,  wliere  tlie>  have  continued  to  the  present  time."  Although  now 
8tructurall>-  very  different  from  the  horse  of  to-day,  they  probably  repre- 
sent something  of  th(^  character  of  the  ancestral  horse. 

The  rhinoceros  (Rhinorcrot'idw)  is  a  relic  of  nature's  early  attempts  to 
formulate  the  solid-hoofed  type  of  quadruped.  It  is  recognized  in  fossils 
toward  the  close  of  the  Eocene  in  both  Europe  and  North  America,  and  the 

I  Ingersoll,  p.  372. 


MAMMALIA 


333 


skeletons  of  those  of  the  Miocene  differ  little  from  those  of  to-day.  These 
once  numerous  and  widely  scattered  animals  are  represented  by  two 
African  and  three  East  Indian  species. 

They  have  three  short  toes  on  each  foot,  each  toe  encased  in  a  hoof-like 
nail.  The  central  or  third  toe  is  the  largest,  but  the  weight  is  sustained  by 
a  sole  pad.  The  East  Indian  forms  (Fig.  270)  have  but  one  nose  horn.  The 
small  Sumatran  form  and  the  African  forms  have  two  horns.  These  horns 
are  simply  outgrowths  of  the  skin  based  upon  a  thickening  of  the  nasal  bone, 
and  are  composed  of  a  number  of  tapering  whalebone-like  fibers,  which 
sprout  from  papillae.  They  are  finely  cemented  together,  growing  at  the 
base  as  fast  as  they  wear  away  at  the  tips.  The  usually  naked  skin  is  very 
thick,  deposited  in  folds,  making  it  look  like  plates  of  armor.  In  fact,  the 
dried  skin  is  used  as  shields  by  the  oriental  soldiers.  The  rhinoceros  feeds 
upon  leaves,  twigs,  and  grass.  It  occasionally  fights  a  tiger  or  leopard. 
It  wallows  in  the  mud.  There  is  but  a  single  calf  at  birth.  The  young  are 
easily  tamed.     Selous  says  the  white  rhinocerous  puts  her  nose  close  to  the 


Fig.  270. — Indian  rhinoceros  {R.  indicus). 


ground  and  guides  the  little  one  (which  precedes  her)  by  keeping  the  point 
of  her  horn  close  against  the  rump.  In  disposition  he  says  they  are  slug- 
gish, inoffensive  animals,  lying  asleep  in  daytime,  and  coniiiig  to  the  water 
to  drink  in  the  evening.      The  African  speei(  s  ure  lihiisli  iiia\  when  clean. ^ 

Th(>  long-lipped  sjiecies  of  Africa  (Rhino'nms  l>irnr'nis)  lias  ;in  over- 
hanging extensible  ujjper  li|)  with  which  it  gras])s  ami  tears  otT  the  leaves 
and  twigs  u))on  which  it  feeds  exclusively.  The  calf  follows  .aloiigsid"  .;if  its 
mother.  So  sharp  is  the  horn  of  a  rhinocerous  and  so  strong  the  liead  and 
neck  that  it  can  "  disembowel  and  to.ss  over  its  back  any  smaller  animal, 
and  it  could  rip  open  an  elephant  if  it  got  at  his  side,  though  some  African 
explorers  say  that  the  rhinocerous  usually  runs  from  a  man ;  but  some  are 
vicious." 

The  horns  are  used  as  knife-handles  and  as  weapons.  The  horn  of  (he 
white  rhinocerous  (/?.  simus)  has  been  known  to  measure  56  inches  long, 
while  that  of  R.  bicornis  is  not  known  to  exceed  40  inches.     The  Chinese 

1  Ingersoll,  p.  3S2. 


334  BRANX'H    CHORDATA 

and  Burmese  "  pay  high  prices  for  the  horns,  tongues,  and  other  efficacious 
parts  of  the  eastern  rhinocerous,  to  be  ground  into  medicinal  powders."^ 

The  horse  {Eq'uidce)  has  the  most  complete  geologic  record  of  any  living 
animal.  P'ossil  remains  were  found  in  the  Eocene  I']])och,  on  which  there 
were  four  front  toes  and  three  hind  ones.  Then  in  tiie  Miocene  were  found 
ancestors  having  three  toes  both  before  and  behind,  while  at  present  this 
family  is  distinguished  by  a  single  functional  toe  on  each  foot,  the  second 
and  fourth  toes  forming  splint  bones  on  either  side  of  the  toe.  The  tibia 
also  is  vestigial. 

In  the  Eocene  times  Europe  and  Asia  were  joined  in  the  arctic  latitudes 
by  way  of  North  America.  The  horse  inhabited  all  continents  except 
Australia,  but  it  disappeared  entirely  from  America  in  the  later  geologic 
ages,  for  which  no  adequate  explanation  has  been  made.^  At  first  it 
was  adapted  to  a  forest  life,  but  it  has  come  to  be  more  and  more  adapted 
to  living  upon  the  high,  dry  plains,  and  it  is  one  of  the  most  highly  special- 
ized animals  in  its  adaptation  to  its  environment.  The  remains  of  man 
and  the  horse  are  first  found  together  in  the  interglacial  or  postglacial 
period.  "There  is  abundant  proof  that  men  first  hunted  and  ate,  then 
drove,  and  finally  rode  the  horse." 

The  horse  industry  stands  second  only  to  the  cattle  industry  among 
stock  men.  Horsehide  leather  is  used  for  razor  straps,  gloves,  and  shoe 
uppers.  The  hair  is  used  for  upholstery  and  the  bones  for  fertilizing,  and 
the  flesh  for  cheap  meat.  The  mare's  milk  is  used  by  the  nomadic  peoples 
of  inner  Asia.  Koumiss,  often  used  as  a  beverage,  is  fermented  mare's 
milk. 

All  our  breeds  of  horses  have  been  introduced  from  the  Old  World,  as 
there  have  been  no  native  wild  horses  in  America.  The  ass,  the  zebra,  and 
the  recently  extinct  African  quagga  are  also  members  of  this  family. 
The  ass  is  wild  in  both  Asia  and  Africa,  and  the  zebra  in  Africa.  The  breed- 
ing of  the  hybrid  mule  is  confined  chiefly  to  the  southern  and  some  of  the 
western  states. 

Artiodactyla. — The  even-toed  ungulates,  in  which  the  third 
and  fourth  digits  form  a  symmetric  pair,  have  the  three  or  four 
premolars  smaller  than  the  molars,  and  have  a  complicated 
stomach. 

The  non-ruminants  comprise  the  hippopotamus,  hog,  and 
peccary.  They  are  omnivorous.  The  canine  teeth  are  fre- 
quently developed  into  tusks. 

The  hippopot'amus  {Hipjiopohun'iila')  is  at  present  confined  to  Africa. 
It  formerly  inhabited  Europe  and  there  were  al.M)  Indian  species  in  the  lower 
Pliocene.  The  common  hippopotanms  (Fig.  271)  is  thick  skinned  and  al- 
most hairless.  The  two  strong  incisors  on  each  side  of  each  jaw  and  the 
canine  teeth  continue  growing  throughout  life.  The  stomach  is  divided 
into  two  parts.  The  cecum  is  lacking.  This  huge  animal,  14  feet  long,  has 
very  short  limbs  and  tail.  The  feet  have  four-hoofed  toes.  The  hippo- 
potamus is  nocturnal  and  aquatic,  and  not  only  walks  rapidly  along  the 

1  Ingersoll,  p.  378. 

2  Ibid.,  pp.  354-360. 


MAMMALIA 


335 


bottom  of  the  river,  but  swims.  It  is  thought  that  it  swam  from  the  Con- 
tinent across  to  Madagascar,  thus  populating  that  island  with  the  genus, 
fossils  of  which  are  found  in  the  swamps.  The  gap  of  the  mouth  is  wide  and 
the  large  teeth  are  used  in  cutting  the  bark  from  trees,  which  is  a  prominent 
feature  of  the  food.  They  produce  a  strange  carmine-colored  secretion, 
"sweat,"  containing  small  crystals  and  corpuscles,  from  the  skin.  "Like 
other  aquatic  animals  the  nostrils  are  on  the  surface  of  the  head  and  can  be 
closed  when  under  water,"  where  it  can  remain  not  over  ten  minutes,  and, 
after  reaching  the  surface  again,  it  spouts  like  a  whale.  It  is  a  dangerous 
animal  to  meet,  as  it  cannot  only  capsize  a  boat,  but  even  bite  out  large 
portions  of  it  and  will  attack  man. 


^'j~z-/i-y  -=.  '■  ;' 


Fig. 


)Tainus   and   young.     (Holder's  "Zoology,"  Americ 
Book  Co.,  Publishers.) 


The  hog  {Suidce)  (Fig.  272)  has  four  toes,  but  only  two  touch  the  ground, 
except  in  miry  places.  The  nostril  is  situated  at  the  end  of  the  tough, 
proboscis-like  snout.  Hogs  are  generally  covered  with  coarse  hair  or  bristles. 
The  stomach  is  simple  and  the  cecum  present.  The  typical  genus  Bus  is 
found  in  Europe,  northern  Africa,  Asia,  and  in  the  Malay  Archipelago. 
The  wild  boar  is  Sus  scrofa  of  Europe. 

The  wild  hog  loves  to  wallow  in  the  wet  ground,  but  sees  to  it  that 
"cover  is  handy."  The  male  is  usually  solitary,  while  the  female  and  young 
go  about  in  groups  of  about  a  dozen.  In  India  it  makes  huts  of  leaves, 
gra.ss,  and  twigs,  so  interwoven  as  to  be  practically  rainproof,  in  which  the 
young  are  housed  for  several  weeks.  The  domestic  pig  has  been  developed 
from  the  wild  hog  by  artificial  sel(>ction  and  intercrossing.  The  African 
wart-hog,  the  ugliest  of  land  animals,  and  Babiru'sa  are  allied. 

The  hog  industry  in  the  I'liited  States  represents  hundreds  of  millions 
of  dollars.  One-third  of  the  hogs  of  the  world  are  produced  here.  Be- 
sides the  pork  used  at  home,  large  quantities  are  exported  to  Europe.     It 


336 


BRANCH    C'HORDATA 


is  said  that  at  the  large  packing-houses  everything  about  the  hog  is  used, 
except  the  squeals.  The  hair  is  sold  for  mixing  mortar  or  for  making  brushes. 
The  skin  is  used  for  making  foot-balls.  The  bones  and  teeth  are  carbonized 
and  sold  to  sugar  refiners  or  ground  into  a  fertilizer.  The  sinews  and  hoofs 
are  used  in  making  glue,  the  intestines  for  sausage-casings,  and  the  blood  for 
making  buttons,  or,  together  with  the  refuse,  for  making  fertilizer. 

American  Hoys. — The  collared  peccary  is  our  best  representative  of  the 
wild  hog.  It  is  grayish  black,  with  a  white  collar  or  streak  about  the  withers. 
It  ranges  from  the  Rio  Grande  in  Texas  southward  to  Patagonia.  It 
prefers  moist,  bushy,  upland  jungles,  but  it  has  been  found  in  regions  sur- 
prisingly dry,  hot,  and  bare  of  vegetation.     Peccaries  go  in  small  droves, 


Fig.  272. — Wild  boar  contrasted  with  a  modern  domesticated  pig.       (Ro- 
manes.) 

and  feed  at  night  on  roots,  mushrooms,  farm  products,  and  small  animals. 
"When  pursued,  they  run  in  open  ground  with  great  fle(>tn('.ss,  and  m  cover 
will  squat  and  dodge  like  a  jack-rabbit."  When  cornered  they  are  cour- 
ageous and  pugnacious,  fighting  viciously,  so  that  the  boldest  hunter  "does 
not  hesitate  to  climb  the  best  tree  that  happens  to  be  available."  Only 
their  courage  and  the  use  of  their  tusks  have  protected  them  from  annihila- 
tion in  forests  infested  with  jaguars,  pumas,  wolves,  and  ocelots.  If  the 
musk  gland  is  cut  out  as  soon  as  the  animal  is  killed  the  flesh  is  palatable. 


The  ruminants,  or  cud-chewers,  include  the  giraffe,  deer,  ox, 
sheep,  and  antelope.     Teeth  and  stomach  are  both  adapted  to  an 


MAMMALIA 


337 


herbivorous  diet.  In  the  upper  jaw  the  canines  are  usually 
degenerate.  There  are  generally  no  incisors,  never  more  than 
a  single  pair,  and  in  their  place  is  a  thickened  calloused  pad. 
The  canines  of  the  lower  jaw  have  taken  the  form  of  incisors. 
The  molars  are  selenodont,  with  crescent-shaped  cusps;  the 
stomach  is  usually  divided  into  four  compartments  (Fig.  273), 
the  rumen  or  paunch,  which  receives  the  food  when  it  is  eaten; 
from  here  it  is  regurgitated  and  chewed  again  as  cud.  It  is 
then  passed  into  the  second  division  of  the  stomach,  the  reticulum, 
from  which  it  passes  into  the  third  division,  the  omasum;  and 
from  there  to  the  true  stomach  or  ahomasum.     These  animals 


Fig.  273. — Stomach  of  a  ruminant  (sheep),  showing  the  four  compart- 
ments: a,  Esophagus;  b,  paunch;  c,  honeycomb  or  reticuUun;  d,  liber 
psalterium  or  manyphes;  e,  true  digestive  stomach;  /,  beginning  of  the  in- 
testine.    (After  Owen.) 

are  usually  large  and  many  of  them  bear  horns,  which  are  larger 
(or  exclusively)  on  the  males. 


The  Chev'rotain  belongs  to  the  primitive  Asiatic  and  African  family 
Tragu'lidce.  It  is  the  smallest  ungulate  living  to-day.  It  has  both  deer- 
like and  pig-like  characteristics.  It  is  hornless  and  the  stomach  has  but 
three  divisions. 

The  camels  and  llamas  {Camel'idce)  have  long  limbs,  with  no  trace  of 
second  and  fifth  toes.  The  rumen  has  smooth  walls,  and  from  it  are  devel- 
oped the  water  cells  (Fig.  274).  Camels  are  wonderfully  adapted  to  their 
desert  home  by  the  sole  pads  on  their  feet;  by  their  sandy  color;  by  their 
long  necks,  which  give  long  range  of  vision  and  enable  them  to  reach  the 
desert  shrubs  on  each  side  of  their  path;  by  their  cartilaginous  mouth,  which 
enables  them  to  eat  the  hard  and  thorny  plants  of  the  deserts  on  which  no 
other  animal  could  subsist;  by  their  small  ears;  by  the  valve-like  folds  by 
22 


338 


BRANCH    CHORDATA 


which  the  large  nostrils  may  be  closed  against  the  simoons  of  the  desert; 
and  by  their  prominent  eyes  and  heavy,  overhanging  eyelids.  The  hump 
is  a  real  and  acknowledged  reservoir  of  nutriment  stored  up  during"  moist 
seasons,  as  well  as  nature's  pack  saddle  for  the  commerce  of  the  ages.^ 
For  centuries  the  camel  has  been  the  means  of  transportation  over  the  desert. 
Papyrus  records  show  it  was  well  known  in  Egypt  at  least  thirty-two 
centuries  ago.  Yet  in  all  these  centuries  "little  of  sympathetic  association 
has  been  gained  between  beast  and  master."  Owing  to  its  viciousness  and 
stupidity  it  has  been  subjugated  rather  than  domesticated.  However,  it 
has  been  developed  into  many  serviceable  forms,  some  swift  and  elegant, 
others  strong  and  ugly. 

There  are  two  distinct  species  of  camels,  the  Bactrian  or  two-humped 
camel  {Came'lus  hactrian.m)  and  the  one-humped  species  ((*.  dromedarius) 
(Fig.  275).  The  two  species  will  interbreed  it  is  said,  and  it  is  not  probable 
that  either  is  now  found  in  a  genuinely  wild  state.  The  camel  is  a  thickly 
built,  ungainly  pack  horse.     The  dromedary  is  the  finer-haired,  light-step- 


Fig.  274. — a,  Water-cells  in  the  paunch  of  the  camel;  h,  foot,  showing 
the  pad.  (From  Holder's  "  Elements  of  Zoology,"  American  Book  Co., 
Publishers.) 


ping  race  horse.  The  former  travels  three  miles  in  an  hour  and  six  hours 
in  a  day,  while  the  latter  can  run  seventy  miles  a  day.  The  latter  is  several 
times  the  value  of  the  former.  The  single  calf  is  weaned  when  about  a  year 
old,  but  it  is  not  fitted  for  service  until  five  years  old.  '  We  are  accustomed  to 
think  of  camels  as  associated  with  heated  countries  alone,  but  the  Bactrian 
camel  can  endure  much  cold,  and  carry  on  the  overland  trade  between  China 
and  Russia  across  the  plains  of  Mongolia  or  Turkestan  amid  the  snows  of 
winter  and  the  dust  of  summer.  Every  spring  the  camel  loses  every  frag- 
ment of  its  hair  and  for  about  twenty  days  it  is  as  naked  as  if  clean  shaven, 
and  is  then  sensitive  to  cold  and  raiii.  When  the  hair,  which  is  at  first  fine 
and  beautiful,  becomes  long  and  thick  it  can  brave  the  severest  frost.  Its 
strong,  elastic,  lustrous  hair  is  woven  into  warm  cloth.  The  Andean  vicu- 
nia  has  finer,  soft,  curly  wool.  The  Arabian  depends  upon  the  camel  for 
many  things:  "fuel,  milk,  hair  for  tents,  ropes,  shawls,  and  coarser  fabrics; 
and  flesh,  leather,  and  bones  from  the  dead  animal.     Camel's  milk,  though 

1  Ingersoll,  p.  337. 


MAMMALIA  339 

bitter  from  the  wormwood  pasturage,  is  the  staple  diet  of  thousands  in 
Africa."  1 

The  genus  Llama  includes  the  llama,  alpaca,  huanaco,  and  vicunia. 
They  differ  from  the  camel  in  their  smaller  size  and  the  absence  of  the  hump. 

The  llama  was  used  in  Peru  as  a  beast  of  burden  for  centuries  before  the 
Spanish  Conquest,  and  is  still  the  only  trustworthy  carrier  in  the  higher 
Andes.  Its  flesh  is  coarse  and  unpalatable,  and  its  hair  is  coarser  and  in- 
ferior to  that  of  the  alpaca.  It  defends  itself  by  "spitting,"  that  is,  forcibly 
ejecting  not  only  the  saliva,  but  the  contents  of  the  stomach  at  any  offender. 
The  discharge  is  injurious  to  man's  eyes.  The  llama  can  also  kick  and 
bite.  The  alpaca  is  a  smaller  variety,  bred  in  Peru  and  Chile  for  its  thick 
growth  of  black  to  gray  or  yellowish  woolly  hair.  "The  Camel-tribe  orig- 
inated in  North  America.  It  is  represented  by  the  Llamas  of  South 
America." — Scott. 


Fig.  275. — One-humped  camel  [Came'lus  dromeda'rius).     (Linnaeus.) 


The  deer  family  (Cer'vidoe)  is  distinguished  from  all  other  ruminants  by  the 
presence  of  true  bony  antlers  in  the  male;  the'  European  reindeer  and  the 
American  caribou  have  antlers  in  both  sexes.  These  antlers  may  be  little 
or  much  branched.  They  are  never  fused  with  the  skull  and  are  usually 
shed  annually.  Each  year  the  new  ones  are  larger  and  provided  with  one 
more  tine.  It  takes  the  antlers  from  ten  to  sixteen  weeks  to  grow  to  matur- 
ity. During  the  greater  portion  of  this  time  the  males  are  weak  and  inof- 
fensive. At  this  time  the  does  are  rearing  the  young  (fawns).  When  the 
new  antlers  are  fully  developed  (about  October)  (Fig.  276)  the  males  are 
as  savage  as  tigers. 

The  white-tailed  Virginia  deer  (Odocoi'leus  virginia'nus)  is  our  most 
widely  distributed  deer.  It  weighs  about  250  pounds,  is  light  brown  in 
summer  and  reddish  brown  in  winter,  with  the  under  parts  of  throat  and  tail 
pure  white.     It  crouches  and  carries  its  head  low,  and  saves  itself  by  clinging 

1  Zwemer. 


340  BRANCH    CHORDATA 

to  the  cover  of  brush  or  timber,  in  which  it  is  not  easily  perceived  until  it 
starts  to  run,  when  it  raises  its  t£^il  and  waves  its  "white  flag"  right  and  left 
in  utter  defiance  of  the  rifle.  If  this  white  tail  is  not  used  as  a  recognition^ 
mark,  it  is  surely  unexplainable. 

The  American  elk  or  wapiti  {Cer'vus  canaden'sis)  is  the  largest  of  the 
round-horned  deer,  handsome  and  tall  as  a  horse,  with  a  luxuriant  mane 
and  imposing  antlers.  The  wild  elks  are  nearly  exterminated  except 
in  Yellowstone  Park,  though  formerly  abounding  from  the  Adirondacks  and 
southern  Alleghenies  to  California  and  even  Alaska.  An  effort  is  being 
made  to  restock  the  Adirondacks,  but  reckless  hunters  make  it  almost  im- 
possible. The  elk  is  both  a  browsing  and  a  grazing  animal.  In  winter 
those  in  Yellowstone  Park  migrate  southward  to  the  sheltering  valleys  of 
Jackson  Hole.    In  summer  they  love  to  ascend  the  high  mountains.    They 


Fig.  276.—"  Pushing  match."     (From  life 


are  kept  in  many  city  parks,  as  they  breed  freely  in  captivity.  The  red 
deer  of  Europe  is  a  close  ally. 

The  reindeer  (Ran'gifer  taran'dus)  of  arctic  Europe  is  unique  in  that  both 
sexes  bear  horns.  These  are  used  not  only  for  defense,  but  to  shovel  snow 
in  search  for  food.  Their  fur  is  of  a  lighter  color  in  winter.  In  Spitzbergen 
they  migrate  "in  the  summer  to  the  inland  region  of  the  island,  and  in  the 
autumn  back  again  to  the  seacoast  to  browse  upon  the  seaweed. "^  Rein- 
deer are  annually  imported  into  Alaska  from  Siberia  for  food  and  burden 
bearers  for  the  natives.  The  multiplication  of  these  reindeer  has  proved  a 
source  of  food  supply.  The  young  develop  into  larger  and  stronger  animals 
than  their  parents. 

Very  closely  allied  is  the  American  caribou,  which  ranges  from  the  east 
coast  of  Greenland  to  the  west  coast  of  Alaska.     Next  to  the  musk-ox  it  is 


1  Glossary. 

2  Beddard,  p.  299. 


MAMMALIA 


341 


the  most  northerly  of  the  ungulates.  The  caribou  is  an  odd-looking  animal, 
with  thick  Ions  lejis  ;in(l  with  hoofs  so  expanded  and  flattened  as  to  make 
good  snow-shoes.  Its  covering  is  warm  and  consists  of  a  "coat  of  fine  wool- 
like hair,  through  which  grows  the  coarse  hair  of  the  rain  coat."  It  feels 
like  a  thick  felt  mat.  The  food  is  moss  and  lichen.  These  animals  migrate 
southward  in  great  herds,  though  they  are  not  known  beyond  the  Churchill 
River.  In  spring  they  return  to  the  most  northern  headlands,  where  they 
bear  their  young.     Upon  these  migrations  the  savages  who  live  in  these 


Fig.  277.- 


-Rocky  Mountain  elk.     (Farmer's  Bulletin  No.  330,  U.  S.  Dept. 
of  Agriculture.) 


arctic  deserts  of  rock  and  snow  depend  for  subsistence.  Every  part  of  the 
animal  is  used.  The  flesh,  stomach,  and  intestines  are  eaten,  as  are  the 
points  of  the  antlers  when  soft,  and  the  marrow  of  the  leg  bones.  Soup  is 
made  from  the  blood  and  meat  mixed  together.  The  hair  forms  the  warmest 
clothing;  also  tents,  cords,  and  shoe-strings.  Knives  and  needles  are  made 
from  the  bones;  fish-hooks,  spears,  and  knife-handles  from  the  horns;  while 
certain  tendons  serve  as  fine  strong  sewing  thread  for  use  with  the  bone 
needles.i 

1  Ingersoll,  p.  323. 


342 


BRANCH  CHORDATA 


The  American  moose  {Al'cc.s  america' nus)  is  the  largest  member  of  the 
family  (Fig.  278),  living  or  extinct,  and  the  male  has  the  heaviest  and  widest 
spreading  antlers. ^  These  are  much  flattened  and  expanded.  The  moose 
has  a  long,  thick,  and  rather  iirehensile  upper  lip,  and  browses  upon  the 
bark,  leaves,  and  twigs  of  certain  trees,  and  upon  moss  and  lichens.  It  is 
as  fond  of  wading  and  swimming  as  a  schoolboy.  It  is  very  fleet,  and  can 
pass  over  large  fallen  tree  trunks  or  a  5-foot  fence  with  ease.  Its  cry  is  a 
long,  resonant  bawl.  The  calf  is  not  spotted.  The  male  has  a  long,  orna- 
mental strip  of  hair-covered  skin,  "the  bell,"  which  in  the  adult  is  sometimes 
a  foot  long.     The  cow  has  neither  antlers  nor  bell.     The  moose  is  easily 


Fig.  278. — The  Alaska  moose  {Alces  americanus  gigas). 
Dept.  of  Agriculture,  1907.) 


(Yearbook,  U.  S. 


handled  and  may  be  trained  to  drive  in  harness,  but  it  does  not  live  long  in 
captivity  except  in  forest  preserves.  Duriiiti  tlic  stormy  winter  "they  herd 
together  in  sheltered  spots  in  the  forest,  ami,  through  moving  about  in  a 
small  area,  the  snow  is  trodden  down  until  llicy  form  a  moose-yard"  of 
several  miles  in  extent.  The  animals  browse  upon  the  twigs  of  adjacent 
trees  and  bushes,  and  with  their  antlers  keep  their  enemies,  the  wolves,  at 
bay. 

"The  so-called  "musk-deer"  differs  from  other  Cervidoe  in  the  absence  of 
horns  and  in  the  presence  of  a  gall-bladder,  tusks,  and  the  musk  gland  of  the 

1  A  pair  of  antlers  from  Alaska  in  the  Field  Columbian  Museum  has  a 
spread  of  78§  inches,  and,  together  with  the  skull,  weighs  93?  pounds. 


MAMMALIA 


343 


male.  These  glands,  or  "pads,"  as  they  are  commercially  called,  form  the 
basis  for  many  nianufactured  perfumes,  and  command  a  high  price,  hence 
these  deer  are  rapidly  diminishing  in  numbers. 

Besides  furnishing  fine  venison  and  the  many  other  articles  already  men- 
tioned, the  deer  family  supplies  "hartshorn,"  or  ammonia.     It  is  made  from 


Fig.  279. — Giraffes  feeding.      (From  Jordan  and  Kellogg's  "Animal  Life,' 
D.  Appleton  and  Co.,  Publishers.) 


the  shavings  and  refuse  left  from  antku's  in  the  manufacture  of  handles  for 
cutlery. 

The  giraffes  (Giraffulce)  have  many  deer-like  characteristics,  but  neither 
sex  bears  antlers.  In  their  stead  they  have  horny  projections  covered  with 
hairy  skin.  The  giraffe  is  the  tallest  of  all  animals,  the  top  of  its  head  being 
18  or  19  feet  from  the  ground.  Its  neck,  though  so  long,  contains  only  the 
same  number  of  vertebrae  (seven)  as  that  of  man.     Each  vertebra  is  length- 


344  BRANCH    CHORDATA 

ened,  still  the  neck  is  not  long  enough  to  reach  the  ground,  so  that  in 
drinking  or  in  reaching  a  tuft  of  grass  the  animal  has  to  straddle  out  his  legs 
and  lower  his  position  (Fig.  279j.  The  giraffe's  eyes  are  large,  dark,  and 
liquid,  and  its  face  has  a  gentle  expression,  but  it  is  sometimes  vicious  and 
fights  by  kicking  either  with  fore  or  hind  feet.  It  has  chocolate-colored 
spots  separated  by  pale  tawny  markings  or  spaces,  but  these  vary  in  both 
pattern  and  shade,  proving  a  souro(>  of  i)rotective  resemblance  in  the  lights 
and  sliaduws  of  the  leafy  trees,  while  the  long  neck  may  be  mistaken  for  a 
weatlKT-beaten  tree-trunk.  The  under  ])arts,  shins,  and  feet  are  whitish. 
The  long  neck  is  useful  in  reaching  the  twigs  of  the  trees  upori  which  the 
girafJe  browses,  and  also  in  allowing  a  wide  range  of  vision,  that  it  may  look 
out  for  lions  and  leopards  in  which  the  long  grass  abounds.     In  locomotion 


Fig.  280.— Head  of  young  ])rong-liorn  antelope.     (After  Hays.) 

the  giraffe  moves  both  the  fore  and  hind  limb  of  each  side  simultaneously, 
giving  it  a  rocking  motion.  Giraffes  are  natives  of  Africa,  there  being  a 
northern  and  a  southern  form. 

The  North  American  prong-horn  {Antiloca'pra  amenca  no)  (Fig.  280) 
seems  to  occupv,  like  the  giraffe,  an  intermediate  stage  between  the  deer 
and  the  true  antelope  on  account  of  the  structure  of  its  horns.  The  horns 
are  branched  in  the  male,  like  those  of  the  deer,  though  having  but  two  or 
three  prongs.  The  horns  of  the  female  are  not  branched.  These  horns— 
that  is,  the  external  portion,  corresponding  to  the  "velvet"  of  the  deer,  but 
which  is  here  a  true  horn— are  shed  annually.  The  prong-horn  has  no 
"false  hoofs."  The  male  is  "about  38  inches  high  and  of  a  varying  yellowish 
brown  above,  darker  on  the  face,  dull  white  on  chin  and  cheeks,  in  two 


MAMMALIA  345 

crescent  patches  across  the  throat,  on  the  under  surfaces,  and  in  a  broad 
heart-shaped  patch  around  the  brown  scut  of  a  tail."  This  whiteness  of 
stern  belongs  in  a  greater  or  less  degree  to  nearly  all  the  ruminants  and  to 
other  gregarious  animals.  It  is  thought  to  be  a  recognition  mark  by  which 
the  young  and  other  members  of  a  herd  follow  the  leader  or  one  another. 
The  prong-horns  are  gregarious.  The  prong-horn  is,  or  used  to  be,  a  crea- 
ture of  the  plains,  living  on  the  dry  bush  grass,  and  avoiding  these  wolf-  and 
wildcat-inhabited  thickets,  but  now  frequently  seeks  their  cover.  The 
young  fawns  (usually  two)  cling  close  upon  the  heels  of  the  mother,  which 
defends  them  with  lowered  horns  and  sharp,  striking  feet.  The  fur  is  use- 
less, but  the  flesh  is  delicious. 

The  cattle  family  {Bo'vidoe)  contains  the  wild  cattle,  the  bison  or  buffalo, 
sheep,  goats,  and  antelopes.  They  are  distiiiguislied  l)y  divided  hoofs  and 
unbranched  horns,  which  consist  of  a  hollow  slieath  growing  over  a  horny 
core,  which  are  never  shed.  As  a  rule  they  are  present  in  both  sexes. 
They  have  no  upper  canine  teeth.  They  are  heribvorous,  preferring  grass 
and  herbage.     Only  a  few  examples  can  be  mentioned  here. 

The  antelopes,  so  far  as  we  know,  are  the  oldest  of  all  bovine  animals. 
They  date  from  tlie  Miocene.  They  differ  from  true  cattle  in  their  more 
graceful  form,  in  that  the  horns,  when  curved,  curve  backward  toward 
the  neck.  Their  skin  is  usually  smooth  and  sleek.  They  are  now  limited 
to  Europe,  Asia,  and  Africa,  predominating  in  tropical  Africa.  The 
sable  antelope  {Hippot'ragus  nVger),  says  Gumming,  "is  the  rarest  and  most 
beautiful  animal  in  Africa.  It  is  large  and  strong,  looking  much  like  the 
ibex.  Its  back  and  sides  are  glossy  black  and  the  under  parts  pure  white. 
The  horns  are  upward  of  3  feet  in  length  and  bend  strongly  back  with  a  bold 
sweep,  reaching  nearly  to  the  haunches."  The  mane  is  erect,  the  hide  satin- 
like, and  the  whole  attitude  fearless  and  noble.  Like  all  the  antelopes,  it 
has  an  equine  form  and  gait.  It  is  readily  tamed  and  seems  able  to  breed 
in  captivity.  These  antelopes  love  to  pasture  on  the  open  plain,  a  few  to- 
gether, mostly  chestnut  cows,  says  Ingersoll,  and  "the  horns  are  used  with 
undaunted  courage  even  when  attacked  by  lions." 

We  cannot  refrain  from  mentioning  the  small,  active,  beautiful  gazelle. 
"The  skin  is  as  sleek  as  satin,  of  a  color  difficult  to  describe,  as  it  varies 
between  the  lightest  mauve  and  yellowish  brown,"  the  belly  and  legs  from 
the  knee  down  are  white,  the  hoof  tapers  to  a  sharp  point.  "The  head  of 
the  buck  is  ornamented  by  gracefully  curved,  annulated  horns,  perfectly 
black,  and  generally  from  9  to  12  inches  long  on  the  bend.  The  eye  is  the 
vtell-known  perfection,  the  full,  large,  soft,  and  jet-black  eye  of  the  gazelle." 
The  Dorcas  gazelles  are  found  in  twos  and  threes  all  over  Egypt.  They  feed 
upon  juicy  plants  and  shrubs,  and  visit  the  crops  at  night.  They  may  stand 
motionless  untii  the  hunter  is  within  rifle  shot  and  then  fairly  skim  the  groud 
in  their  flight. 

A.ssociated  with  the  antelopes  are  the  ugly  gnus  of  South  Africa. 

Sheep  and  goats  are  very  closely  allied,  the  goats  differing  from  the 
sheep  in  their  -slight  build,  in  the  beard  of  the  male,  and  in  the  horns,  which 
are  arched  over  the  back  instead  of  spirally  curved,  as  is  the  rule  with  sheep. 

True  goats  {Ca'pra)  are  almost  exclusively  Patearctic.  They  are  repre- 
sented by  the  Spanish  ibex  iC .  iiijrnKiinA.  tlie  steinbock  {C.  ibex)  of  the 
Alps  and  Tyrol,  and  the  Persian  wild  gd.il  (' '.  lujiuinis).  The  Persian  wild 
goat  is  probably  the  principal  species  frdin  w  iiicli  tlie  tame  goats  are  derived. 
According  to  Mr.  Blanford,  the  "bezoar  stones,"  the  concretions  of  various 
lime  salts  found  in  the  stomach,  were  supposed  to  be  of  great  virtue  as  an 
antidote  for  poison.     One  stone  of  4  ounces  once  sold  in  Europe  for  £200. 


346 


BRANCH  CHORDATA 


Geologically,  goats  are  traced  back  to  the  Pliocene.  Their  distribution  is 
limited  and  varied,  owing  chiefly  to  their  mountain-loving  nature.  Their 
different  environments  and  tendeni;y  to  vary  have  given  rise  to  many  and 
very  various  breeds  of  the  domestic  goat. 

The  goats  of  central  Asia,  living  in  a  climate  of  great  extremes  of  tempera- 
ture, furnish  the  fine  wool  of  Cashmere  and  Thibet,  which  is  their  under  coat. 
The  Angora  goat  of  Asia  Minor  furnishes  millions  of  pounds  annually  of 
long  silky  hair.  The  cashmeres  and  mohairs  of  our  stores  are  from  goat 
hair  and  wool.  The  leather  from  goat  hide  is  alwaj's  valuable,  especially 
that  of  morocco,  while  the  skin  of  the  kid  is  valued  for  gloves.  The  goat 
has  for  many  centuries  been  used  as  a  domestic  animal.  It  supplies  an 
abundance  of  good  milk,  rich  in  cheese-making  casein,  and  requires  much 
less  food  than  the  cow.  In  southern  Europe  herds  of  goats  are  driven  from 
house  to  house  and  milked  at  the  door  of  each  customer,  and  then  driven 


Fig.  281. — Rocky  Mountain  goat  {Haploc'tros  monla'nus). 


back  to  pasture.     The  goat  readily  cleaves  to  the  household  and  exhibits 
more  intelligence  than  other  members  of  our  flocks  and  herds. 

The  chamois  of  the  European  Alps  and  the  Rocky  Mountain  goat  (Fig. 
281)  are  described  as  goat  antelopes.  The  Rocky  Mountain  goat  is  the 
nearest  we  have  to  the  goat,  for  this  is  not  a  true  goat  nor  a  true  antelope. 
It  is  twice  as  large  as  a  goat  and  looks  much  like  a  miniature  buffalo,  only 
its  pelage  is  pure  white,  soft,  and  fine.  Its  hoofs,  horns,  and  nose  are  black. 
"It  has  high  shoulders,  low  hind-quarters,  thick  legs,  and  neck.  It  carries 
its  head  low.  Its  face  is  long."  The  small,  angular  hoofs  consist  of  a 
pad  inside  and  a  knife-edge  outside,  equally  adapted  to  snow  or  bare 
rock.  It  "inhabits  thr  grassy  belt  of  high  mountains  just  above  timber  line, 
and  loves  the  dangerous  ice-covered  slopes,"  being  able  to  ascend  almost 
perpendicular  precipices.  It  is  exceedingly  difficult  to  capture  and  does  not 
live  long  in  captivity.     "It  is  now  found  in  only  Idaho,  Washington,  and 


MAMMALIA 


347 


northwest   Montana.     It  is  scattered  at  long  intervals  through  British 
Columbia  and  Alaska,  as  far  as  the  head  of  Cook's  inlet. "^ 

The  sheep  (Ovis)  are  almost  entirely  palaearctic  and  nearctic,  barely 
getting  into  the  oriental  region.  They,  like  the  goats,  are  often  limited  to 
islands  and  small  stretches  of  country,  owing  in  part  to  their  mountain- 


Fig.  282.— The  White  Mountain  .sheep  of  Alaska  (Oi'is  dalli).     (Osgood, 
Yearbook,  1907,  U.  8.  Dept.  of  Agriculture.) 


loving  habits  (Fig.  282).  There  are  six  North  American  species.  The 
Rocky  Mountain  big-horn  {Ovis  monlana)  ranges  from  the  far  north  to  New 
Mexico.  The  mountain  sheep  is  a  fine,  sturdy  animal,  bold,  keen-eyed, 
active,  and  strong.  It  fears  no  storm  and  defies  all  enemies,  save  man  with 
his  gun  and  domestic  sheep  with  their  diseases.  It  deHghts  in  the  highest 
1  Hornaday. 


348  BRANCH    CHORDATA 

crags  of  the  mountains,  the  boldest  rim-rock  of  the  plateau,  or  the  most 
rugged  "bad  lands,"  for  which  it  is  adapted  by  its  round  firm  hoofs,  its 
warm  winter  under  coat,  its  ability  to  subsist  on  scant  herbage,  and  its  keen 
senses.  It  is  hunted  by  mountain  lions  and  by  man  for  its  savory  flesh. 
It  has  a  handsome  head  and  massive  horns  curved  into  the  half  or  three- 
fourths  of  a  circle,  as  are  the  horns  of  no  other  wild  animal.  It  needs  to  be 
seen  in  its  native  cloudland  to  be  fully  appreciated. 

There  are  many  breeds  of  the  domestic  sheep.  The  original  of  this  per- 
haps most  useful  and  least  educated  of  animals  is  not  known.  The  variation 
of  external  characters,  such  as  horns,  ears,  and  tail,  and  in  the  color,  length, 
texture,  and  quality  of  the  fleece,  is  exceedingly  great.  The  existence  of 
these  numerous  breeds  is  probably  due  to  their  tendency  to  varj'  and  to 
effect  fertile  crosses,  and  to  long-continued  selection,  combined  with  the 
obstinacy  with  which  these  variations  are  transmitted  and  retained.  Sheep 
are  used  to  an  enormous  extent  both  for  the  production  of  their  wholesome 
flesh  and  for  their  wool.  Thousands  of  Persian  lamb  skins  are  used  in  the 
fur  trade  annually,  and  hundreds  of  thousands  of  Astrakans,  which  is  the 
same  breed  taken  when  exceedingly  young,  it  is  said,  before  their  natural 
birth.  This  breed  is  also  greatly  valued  for  its  fat,  which  accumulates  on 
the  haunches  in  two  great  protuberances.  In  the  fat-tailed  sheep  of  Asia 
the  tail  of  pure  fat  sometimes  weighs  30  to  50  pounds,  and  trails  upon  the 
ground  if  not  suspended  upon  wheels  or  carried  upon  a  truck.  This  fat 
is  regarded  as  a  great  luxury.  The  Spanish  Merino  sheep  has  been  intro- 
duced into  South  Africa,  Australia,  and  the  United  States.  It  is  celebrated 
for  the  line  (|uality  of  its  wool. 

The  musk-ox  {O'vihos  mosclia'lus)  is  a  strange,  long-haired,  short-legged 
creature  of  the  frozen  North.  It  belongs  between  the  sheep  and  ox,  par- 
taking of  the  characters  of  each. 

Oxen  are  distinguished  from  other  hollows-horned  ruminants  by  their 
stouter  build,  and  by  their  smooth  curved  (not  twisted)  horns,  which  stand 
out  from  the  sides  of  the  head.  The  wild  ox  of  Europe  (Bos  primigenius) , 
believed  to  be  surviving  in  the  herds  of  Chillingham  and  Chartley,i  is 
supposed  to  be  the  progenitor  of  our  cattle.  The  original,  called  the  auroch, 
or,  by  the  Romans,  Urus,  was  of  more  gigantic  size. 

One  of  the  largest  of  the  family  to-day  is  the  European  bison  (Bos 
bonasus).  It  looks  much  like  our  American  bison  or  buffalo,  but  is  taller. 
Bisons  differ  from  oxen  in  having  a  hump  over  the  shoulder  formed  by 
spinous  processes  for  the  attachment  of  the  great  muscles  used  in  holding 
up  the  massive  head  and  in  the  great  pushing  matches  of  the  bulls.  The 
American  "buffalo"  is  more  shaggy  and  robust  than  the  European  "wisent  " 
(Fig.  283).  The  latter  was  forest  inhabiting,  while  our  "buffaloes"  loved 
the  plains,  where  they  congregated  form.erly  in  great  herds  in  spring  and  fall, 
but  usually  formed  only  scattered  bands  which  traveled  over  the  plains  in 
single  file.  The  true  buffalo  of  Africa  and  India  has  no  hump  and  is  almost 
hairless.  No  animal  is  more  dangerous  than  an  infuiiated  bull  buffalo,  and 
none  more  easily  provoked.  Pugnacity  and  revenge  are  its  ruling  impulses. 
It  has  been  domesticated  in  India,  and  is  very  useful,  but  not  lovable. 
Africa  has  two  species,  which  are  sometimes  accompanied  by  starlings. 
In  the  East  starlings  and  herons  "perch  on  their  backs  and  hunt  for  ticks 
and  other  parasites" — a  strange,  but  mutually  beneficial  commensalism. 

The  yak  {Bos  grunniens),  of  the  mountains  of  Thibet,  has  short  legs, 
goat-like  feet,  humped  shoulders,  smooth,  spreading  horns,  and  carries  its 

iPeddard,  p.  321. 


MAMMALIA 


349 


head  low.  From  the  chin,  throat,  and  lower  parts  of  the  sides  the  hair 
grows  long  and  forms  a  fringe,  a  wonderful  adaptation  to  the  climate.  This 
long  hair  serves  as  a  mat  beneath  it  when  it  lies  down  upon  the  ice  and  snow, 
as  well  as  a  warm  cover  under  which  it  curls  its  legs.  The  tail  is  thick  and 
silky,  sometimes  6  feet  long.  It  is  often  beautifully  mounted  on  antelope- 
horn  handles  and  used  for  fly-whisks  in  the  East.  The  cry  is  much  like  the 
grunt  of  a  pig,  but  louder  and  longer.^  Tame  yaks  have  long  been  used  as 
strong,  sure-footed  beasts  of  burden.  The  flesh,  milk,  and  butter  are  ex- 
cellent. From  its  hide,  clothing,  tent  covers,  and  harness  are  made,  and  the 
hair  is  twisted  into  ropes. 


Fig.  283. — A  group  of  buffaloes,  "  American  bison  "  (Bos  americanus)  in 
Yellowstone  National  Park.     (From  life.) 

The  numerous  breeds  of  domestic  cattle  form  an  enormous  industry. 
The  exports  of  the  United  States  alone,  such  as  cheese,  butter,  hides,  tallow, 
and  beef,  amount  to  many  million  dollars  annually. 


Geologic  Distribution  of  Ungulates. — The  camel  is  represented 
in  the  OHgocene.  The  Miocene  forms  in  America  had  horns 
something  Hke  deer  antlers.  The  Procamelus,  the  probable 
ancestor  of  both  camels  and  llamas,  flourished  in  the  Miocene. 
In  the  Pliocene,  Europe  had  deer,  antelopes,  oxen,  and  the  first 
'  Ingersoll,  p.  247. 


350  BRANCH    CHORDATA 

Old  World  camels,  as  well  as  giraffe-like  forms.  "That  the 
camel  got  the  pads  on  his  feet,  the  water-pockets  in  his  stomach, 
and  the  other  drought  and  sand  resisting  arrangements  from  an 
ancestor  that  began  in  the  United  States  a  million  or  more  years 
years  ago  "  has  been  proved  by  Cope,  Doctor  Wirtman,  and  his 
assistants.  The  oldest  fossil  deer  types  are  Miocene.  They 
were  sniall,  hornless  creatures.  The  first  horned  deer  were  in 
the  middle  Miocene,  when  the  horns  were  bifid.  The  giraffe, 
or  its  close  allies,  existed  in  the  Miocene.  The  bison  existed  in 
the  Miocene,  as  shown  in  fossil  Bos  sivalensis  from  India.  The 
Pliocene  life  included  a  variety  of  oxen  and  two  North  American 
bisons. 

Order  VII.  Rodentia  or  Gli'res. — Rodents  are  exceedingly 
numerous  and  well-known  mammals,  covered  with  fur  or  spines. 
They  are  generally  small,  varying  in  size  from  the  porcupine,  of 
about  3  feet  in  length,  to  some  of  our  small  mice,  not  over  4  or  5 
inches  long. 

The  one  distinguishing  characteristic  of  rodents  is  their  teeth. 
(See  Fig.  288,  p.  355.)  These  have  enamel  on  their  front  surfaces 
only.  Thus,  their  incisors,  which  grow  continuously  from  per- 
sistant pulps,  are  always  chisel  shaped  and  kept  sharp  by  the 
wearing  away  of  the  posterior  surfaces.  There  are  never  more 
than  two  incisor  teeth  in  the  lower  jaw,  and  only  two  in  the 
upper,  except  in  Lepor'idce,  where  there  are  four.  The  lack  of 
canine  teeth  in  all  rodents  leaves  a  space  or  diastema  between 
the  incisors  and  the  molars.  The  molars  vary  in  number  from 
two  to  six  on  each  side  of  each  jaw.  There  is  a  hairy  ingrowth 
in  the  mouth  back  of  the  incisors,  which  serves  to  catch  the 
particles  when  the  animals  are  gnawing.  They  are  usually 
vegetable  feeders,  but  some  are  carnivorous  or  omnivorous. 
The  intestine  is  long  and  the  cecum  large  (except  in  dormice)  and 
often  complicated. 

As  a  rule  the  clavicle  is  present.  Most  rodents  are  five  toed. 
The  toes  have  claw-like  nails.  They  are  usually  plantigrade  or 
semiplantigrade.  The  cerebrum  is  small  and  nearly  or  quite 
smooth,  but  in  some  of  the  larger  forms  (the  beaver  excepted) 
it  is  well  convoluted.  The  ears  and  eyes  are  well  developed. 
The  voice  is  a  squeak  or  squeal.  Their  defense  is  by  spines, 
as  in  the  porcupine;  by  biting,  as  in  the  rat;  and  by  flight  or 


MAMMALIA  351 

concealment,  as  in  the  rabbit,  though  the  rabl^t  will  fight  vi- 
ciously by  biting  and  by  striking  with  its  hind  feet  if  cornered,  or 
if  the  nest  or  "  form  "  containing  the  young  is  attacked. 

Some  hibernate  in  winter,  others  migrate  in  flocks.  They  live 
almost  everywhere,  but  are  chiefly  terrestrial;  some  are  aquatic, 
some  subterranean,  and  still  others  arboreal.      They  are  very 


Fig.  284. — American  flying  squirrel  (Sciurop'terus  voluceUa).     (From  Pack- 
ard's "Zoology,"  Henry  Holt  &  Co.,  Publishers.) 

prolific,  the  young  being  numerous,  and,  in  some  families,  four  to 
six  litters  a  year.  Since  they  are  hardy,  often  nocturnal,  and  not 
very  particular  as  to  the  character  of  their  food  or  lodging,  they 
have  become  worldwide  in  distribution. 

Squirrels  iSciii' rider)  are  worldwide,  excepting  .Australia  and  Madagascar. 
The  eyes  ami  cais  are  large,  the  tail  long  and  bushy,  the  iliuiiibs  on  the  fore 
feet  inconspicuous      There  are  four  toes  on  the  hind  feet  and  the  tibia  and 


352  BRANCH    CHORDATA 

fibula  are  distinct.  They  feed  upon  nuts  and  grain,  as  well  as  eggs  and 
young  birds.  They  are  chiefly  arboreal,  building  their  nests  in  tree-tops. 
They  lay  up  a  store  of  food  in  hollow  trees,  where  they  pass  the  severe 
winter  weather.  Four  species  of  this  genus  (Sciurus)  are  found  in  the 
United  States  and  Canada.  S.  vulgaris,  the  common  squirrel  of  Great 
Britain,  is  found  from  Ireland  to  Japan. 

Flying  squirrels  (genus  Sciurop'terus)  (Fig.  284)  of  the  palsearctic  region 
(which  includes  Europe,  northern  Asia  and  Japan,  North  America,  and 
India)  have  a  furry  membrane  connecting  the  anterior  and  posterior  limbs. 
This,  together  with  the  broad  tail,  acts  as  a  sort  of  parachute,  enabling  these 
squirrels  to  take  enormous  downward  leaps  from  limb  to  limb  or  tree  to 
tree.  They  cannot  "fly"  upward,  but  ascend  the  tree  by  climbing.  The 
Asiatic  flying  squirrel  is  16  to  18  inches  long  without  the  tail,  and,  it  is  said, 
80  yards  have  been  covered  in  their  longest  leaps. 

The  little  striped  ground  squirrel  {Tamias  striatus)  burrows  and  carries 
its  food  in  its  check  i)oiiclies  to  its  nest  in  the  ground. 

The  prairie-dog  (genus  Cy'nomys),  of  the  great  western  plains,  is  also  sub- 
terranean, digging  a  burrow  and  throwing  up  a  mound  at  its  entrance. 
There  are  whole  villages  of  these  mounds,  sometimes  covering  acres.  The 
prairie-dog  hibernates  in  winter,  at  least  comes  out  only  occasionally.  One 
kept  in  a  cage  by  the  author  comes  out  of  his  "straw  burrow"  at  night  or 
just  before  dawn,  only  at  long  intervals,  for  food.  They  sit  up  on  their 
hind  feet  and  look  all  around  like  sentinels,  but  dart  back  into  their  burrows 
again  at  the  least  approach  of  danger,  uttering  a  shrill  cry  as  a  warning  to 
the  rest  of  the  community.  They  are  so  quick  of  movement  that  it  is  diffi- 
cult to  shoot  or  trap  them.  Their  ears  are  small.  Their  legs  are  so  short  - 
that  in  running  they  "hug  the  ground,"  of  which,  in  sandy  regions,  they  are 
very  nearly  the  color.  They  grasp  their  food  with  their  paws  like  true 
squirrels. 

The  marmots  of  the  arctic  regions  are  closely  allied  to  these.  The  Alpine 
marmot  {Ardo'mys  marmotta)  lives  far  up  in  the  Alps.  Its  danger  signal  is 
a  shrill  whistle.  Th(>8e  inannots  hibernate,  ten  to  fifteen  being  packed 
together  in  a  well-lined  burrow. 

The  North  American  beaver  (family  Castor'idce)  is  an  aquatic  rodent  with 
a  stout  body,  flat,  scaly  tail,  and  webbed  hind  feet.  It  fells  trees  by  means 
of  its  strong  incisors,  damming  the  stream  so  as  to  raise  the  level  of  water 
above  the  entrance  to  its  burrow.  The  beaver  (Castor  canadensis)  is  fast 
becoming  exterminated  on  account  of  the  demand  for  its  fur. 

Rats  and  mice  {Muridce)  have  naked  tails  which  are  scaly  underneath. 
The  soles  of  the  feet  are  naked  and  the  tibia  and  fibula  are  united  below. 
Some  of  the  numerous  genera  are  found  in  all  parts  of  the  world.  The 
muskrat  is  the  largest  member  of  this  family.  Some  of  the  species  are 
among  the  smallest  quadrupeds  known . 

The  North  American  muskrat  (genus  Fiber)  is  a  genus  of  two  species  of 
dark  brown  aquatic  animals.  They  dig  burrows  in  the  banks  of  streams,  the 
entrances  to  which  are  beneath  tiie  surface  of  the  water.  The  hind  feet 
are  slightly  webbed,  the  tail  flalieiieil  and  scaly,  with  scattered  hairs. 
The  shortened  thumb  has  a  fully  (le\  eloped  claw,  and  they  grasp  theii  food, 
which  consists  of  roots  and  water  plants,  with  their  paws,  like  the  squirrels. 
A  Rocky  Mountain  species  [Filter  osoyoosensis)  is  said  to  construct  a  dome- 
shaped  house  of  "buhnishes"  in  the  water.'  It  feeds  largely  upon  water- 
fowls and  fish. 

The  common  mouse  (Miis  mus'culus)  and  rat  {M.  decumanus)  have 
been  introduced  into  America  from  the  Old  World.     M.  minutiis  is  said  to 


MAMMALIA 


353 


be  the  smallest  British  quadruped,  except  the  lesser  shrews.  It  is  2^  inches 
long  without  the  tail,  which  is  the  same  length.  The  water  rats,  or  voles, 
represent  another  genus,  also  the  meadow  mice  or  "field  mice"  (.^rirrnfjts) 
(Fig.  285).  The  typical  field  mouse  is  a  "short-eared,  short-bailed,  thick- 
set" little  creature  4J  inches  long,  with  a  tail  U  inches  long.  It  is  hrown 
above  and  white  or  grayish  below.  It  is  found  from  the  Atlantic  to  the 
Dakotas.  It  feeds  on  grass,  roots,  and  grain.  In  severe  winters  t  liey  .some- 
times do  much  damage  by  eating  the  l)urk  of  young  trees  (Fig.  2,S(J). 

Dormice. — The  common  dormouse  of  tlie  Old  World  {Muscanli'nus  avel- 
lanarius)  has  a  long  bushy  tail  :ind  looks  much  like  a  tiny  squirrel.  Its 
body  is  "3  inches  long  with  a  tail  22  inches  long." 


Fig.  285 


-Carson  field  or  meadow  mouse  (Microt'us  montanus) 
U.  8.  Dept.  of  Agriculture,  1908.) 


(Yearbook 


The  American  porcupines  are  chiefly  arboreal.  The  quills,  which  are 
but  an  inch  or  two  long  and  are  somewhat  hidden  among  the  intermingled 
hairs,  are  loosely  attached,  so  that  when  an  animal  comes  in  contact  with 
them  they  stick  "into  it,  and,  being  barbed,  they  pull  out  of  tiie  jxircupine  and 
remain  in  the  enemy.  Hence  ])orcupincs  are  considered  a  nuisance  by  cat  tie- 
men  of  the  West.  They  are  also  annoying  to  the  lumbermen  of  the  North, 
as  they  gnaw  the  wooden  handles  of  their  tools.  Tliese  animals  are  so  well 
protected  by  their  spines  that  they  need  little  intelligence  to  escajte  their 
enemies,  and  are  rather  stupid.  The  Old  World  porcupines,  by  .some 
authorities  placed  in  another  family,  have  spines  a  foot  in  length.  On  the 
tail  are  hollow  ((uills,  which  make  a  rattling  noise  somewhat  like  that  of  the 
rattlesnake  to  warn  t  he  enemy.  The  South  American  genus  has  a  prehensile 
tail.  The  little  guinea-pigs  are  South  American  relatives. 
23 


354  BRANCH    CHORDATA 

Jumping-mice  ( Dijiud'ida)  (F'\g.  287)  are  represented  by  the  American 
jumping  inifc  and  ihc  Palaantic  Jerboas.  They  have  long  tails  and  the 
hind  legs  are  greatly  elongated  and  adapted  for  taking  enormous  leaps. 


Fig.  286. — Lombardy  poplar  killed  by  field  mice.     (Farmer's  Bulletin 
No.  33.5,  U.  S.  Dept.  of  Agriculture,  October,  1908.) 


Fig.  287. — Jumping  mouse.     (After  Tenney.) 

The  pouched  gophers  (Geomy'idce)  have  large  cheek  pouches  opening  ex- 
ternally (Fig.  288,  a,  b,  c).  These  burrowing  rodents  are  restricted  to  Cen- 
tral America  and  the  central  plains  of  North  America.  They  have  small  ears 
and  eyes.     The  claws  of  the  anterior  limbs  are  strong. 


MAMMALIA 


355 


The  family  Leporidae  is  represented  by  hares  and  rabbits.  Formula  for 
the  teeth:  Incisors,  „;  molars,  — ,  or  28  in  all.  One  pair  of  upper  incisors 
is  much  smaller  and  immediately  behind  the  other.     This  arrangement  of 


-Faces  of  pocket  gophers,   showing  pouches   and  incisors: 
a,  Geomys;  b,  Cratogeomys;  c,  Thomomys.     (Yearbook  U.  S.  Dept.  of  Agri- 


Fig 
Geoi 
culture,' 1909.) 


the  incisors  has  iii\cii  ris(>  to  the  term  DupUcidenta'ta.  The  soles  are  furred, 
thetail  short  ami  i(<ur\cd,  the  eyes  large,  and  the  ears  long.  ThehindHmbs 
(Fig.  289)  are  longer  llian  the  fore  limbs  (Fig.  290),  and  they  "run"  by 


Fig.  289. — Posterior  limb  of  Jack-rabbit.     (Mounted  by  students.) 


prodigious  leaps.  Genus  Lipus  cont; 
common  forms  in  the  Ihiitod  States  ai 
the  marsh  hare  (L.  palustrit;);  the  watei 


ns  thirty  or  forty  species.  Our 
:  tlie  "cotton-tail"  (L.  sylvaticus); 
rabbit  (L.  aqualicus),  also  a  south- 


356  BRANCH    CHORDATA 

em  form;  the  Jack-rabbit  (L.  campeslris)  of  the  West  and  Southwest;  and 
L.  americanus,  a  northern  variable  species,  whose  fur  turns  white  in  winter. 
They  are  not  gregarious,  though  it  is  said  they  often  play  together  on  moon- 
light nights.     They  are  crepuscular  and  somewhat  nocturnal. 

Geologic  Distribution. — Rodents  appeared  first  in  America  in 
the  Wasatch  stage  of  the  Eocene.  Ahnost  all  the  principal 
groups  of  existing  forms  appeared  within  the  tertiary.^ 

Use  to  Man. — Great  numbers  of  rabbits  are  used  for  food  in 
the  cities  during  the  winter  season.     Their  fur  is  used  for  making 


Fig.    290. — Scapula    and    anterior    limb    of    Jack-rabbit.     (Mounted    by 
students.) 

felt  hats.  "  Nine-tenths  of  the  felt  hats  worn  in  the  United 
States  are  made  from  rabbit-fur."  Where  they  are  numerous 
or  food  is  scarce  they  gnaw  the  bark  of  young  fruit  trees.  In 
many  localities  the  orchard  is  enclosed  in  rabbit-proof  fence. 
Beaver  skins  are  also  much  used  for  furs. 

Order  VIII.  Carniv'ora  ("  Mammals  of  Prey  "). — These  flesh- 
eating  mammals  may  be  small  or  large.  They  may  be  terres- 
trial, arboreal,  or  aquatic.     They  feed  upon  the  flesh  and  blood 

^  Parker  and  Haswell,  p.  574. 


MAMMALIA  357 

of  other  animals,  which  they  catch  l\y  cunning,  by  chasing, 
or  by  stealthily  creeping  up  and  pouncing  on  them,  where- 
upon they  bite  and  tear  them  in  pieces.  Here  we  found  an- 
other striking  illustration  of  the  adaptation  of  structure  to 
habits.  They  must  be  fitted  to  attack  and  destroy  other  ani- 
mals. Their  five  or  four  toes  are  armed  with  sharp  claws,  which, 
in  the  cat,  are  retractile  into  a  sheath  by  which  they  are  pro- 
tected when  not  in  use.  The  teeth  are  adapted  for  seizing, 
biting,  holding  or  cutting,  in  contrast  to  the  nibbling  or  grind- 
ing teeth  of  the  herbivores.  The  usually  six  incisor  teeth  are 
small.  The  canines  are  long,  strong,  and  conical,  fitted  for 
tearing,  and  the  premolar  in  the  upper  jaw  and  the  first  molar 
in  the  lower  jaw,  called  the  "  carnassial  teeth,"  are  developed 
into  thin,  sharp,  three-pointed  fangs,  shutting  down  past  one 
another  like  scissor-blades,  while  the  cusps  of  the  molars  form 
more  or  less  angular  and  sharp  ridges. 

The  stomach  is  simple,  and  the  cecum  small  or  wanting. 
The  clavicle  is  reduced,  the  radius  and  ulna  well  developed. 
As  to  manner  of  walking,  there  are  several  gradations  from  the 
plantigrade  bears,  which  walk  on  the  soles  of  their  feet,  to  the 
digitigrade  cats,  which  walk  on  the  tips  of  their  toes.  The 
coloration  is  varied  to  conform  to  their  habits.  Some  are 
spotted,  others  striped,  while  many  adults  are  quite  modest  in 
their  plain,  uniform  colors.  The  brain  is  large  and  well  convo- 
luted, and  the  sense  organs  well  developed,  giving  them  a  high 
degree  of  intelligence. 

This  provision  of  nature,  wherein  some  animals  feed  upon 
vegetable  matter  and  others  feed  upon  animals — for  every  living 
thing,  from  the  microscopic  algae  in  the  water  to  large  animals 
like  the  deer  and  horse,  becomes  food  for  some  animal— is  a 
wise  one.  For  thus  the  vegetation  of  the  earth  supports  not  only 
the  herbivorous  animals  feeding  directly  upon  it,  but  the  carniv- 
orous animal  has  his  food  very  largely  prepared  for  him  by  the 
vegetable-feeding  animals.  But  the  carnivorous  animal  also 
aids  the  herbivorous  survivors  in  their  struggle  for  existence,  for, 
was  not  the  number  kept  within  bounds,  the  rapidly  multiply- 
ing herbivores  would  soon  absolutely  destroy  the  vegetation  of 
the  world. 

These  animals  are  usually  clothed  in  dense,  soft  hair,  and 


358 


BRANCH  CHORDATA 


many  of  them  are  valuable  for  their  fur.     The  cat  and  dog  have 
been  domesticated. 

The  Terrestrial  Carnivora  (Fissipe'dia). — The  number  of 
digits  may  be  five  on  each  foot,  but  is  often  reduced  to  four  on 
the  hind  feet,  as  in  cats  and  dogs,  and  sometimes  to  four  on  the 
front  feet,  as  in  Hyce'nidce,  but  the  reduced  first  toe  may  bear  a 
claw. 

The  cat  family  (Fe'lidce)  includes  the  lions,  tigers,  leopards  or  pan- 
thers, jaguars,  pumas,  lynxes,  wildcats,  etc.  They  are  widely  distributed 
in  both  the  Old  World  and  the  New,  but  are  absent  in  Australia. 
They  seem  to  have  evolved  in  the  Old  World  first,  migrating  to  North 
America  at  the  close  of  the  Pliocene,  and  from  thence  to  South  America. 
The  legs  are  relatively  short  and  the  claws  are  retractile.      The  terminal 


Fig.  291. — Bones  and  ligaments  of  the  toe  of  a  cat,  slK)wing  the  claw  re- 
tracted {A)  and  protruded  (B). 


joint  bearing  the  claw  (Fig.  291)  folds  back  into  a  sheath  by  the  outside 
of  or  above  the  middle  joint,  and  is  held  there  by  a  strong  ligament.  This 
is  the  natural  position  of  the  claw  and  prevents  it  from  friction.  When 
wanted  for  aggression  or  defense  it  is  pulled  into  position  by  the  flexor 
muscles  bearing  the  claw. 

The  raccoons  {Prociion'idcB),  placed  by  some  with  the  bear  family,  are 
plantigrade  and  omnivorous,  eating  anything  in  the  way  of  fish,  oyster, 
crayfish,  flesh  or  fowl,  and  green  vegetables  especially  corn.  They  have 
the  peculiar  habit  of  washing  their  food.  Th(\v  are  nocturnal.  The  limbs 
are  long  and  the  soles  of  the  feet  naked.  "The  raccoon  is  at  home  in  the 
timbered  regions  of  the  southern  and  eastern  United  States  where  there  are 
swamps,"  for  it  loves  to  play  and  to  fish  in  the  water.  It  has  long  active 
fingers,  and  uses  its  hands  as  cleverly  as  a  monkey.  It  makes  its  home  in 
the  hollow  limb  of  a  tree.  The  annual  family  of  five  or  six  young  follow  the 
mother  about  for  a  year.  In  August  the  "coons"  are  fat  and  the  flesh  is 
tender  and  juicy,  and  "coon  hunting"  is  a  great  sport.     The  young  are  easily 


MAMMALIA  359 

tamed,  but  are  annoying  on  account  of  their  curiosity  and  the  skill  with 
which  they  open  doors  with  their  hands.  The  fur  is  much  used.  The  fam- 
ily includes  also  the  civet-cats  of  the  Southwest,  the  kinkajou  of  the 
trojiics,  and  the  South  American  coati. 

The  bears  (  Ur'^id(e)  are  clumsy,  omnivorous  animals,  with  thick  limbs 
and  naked-soled,  i)lantigrade  feet,  bearing  strong  non-retractile  claws. 
The  tail  is  short  and  the  hair  coarse.  The  "molar  teeth  arc  more  adapted  to 
grinding  than  to  cutting  and  the  flesh  teeth  are  massive  and  blunt."  Some 
species  are  especially  fond  of  insects,  such  as  day-flies,  grubs,  and  termites. 
The  latter  they  obtain  by  digging  into  the  nest  and  sucking  them  into  the 
mouth  with  inlaalations  strong  enough  to  be  heard  two  hundred  yards  away. 
They  are  also  fond  of  honey  and  fish.  They  live  upon  the  ground,  few  spe- 
cies being  able  to  climb  trees.  The  den  may  be  in  a  hollow  tree  or  in  a  cave 
in  a  hillside,  either  natural  or  dug  out  by  the  mother.  Two  cubs,  not  larger 
than  rabbits,  almost  hairless,  blind,  and  helpless,  are  born  in  mid-winter, 
and  the  mother  guards  them  solicitously.  It  takes  seven  years  to  reach 
maturity.  Bears  rarely  breed  in  captivity.  The  male  bears  wander 
alaout  singly,  "the  females  are  accompanied  by  their  cubs,  often  as  big  as 
themselves." 

Bears  are  naturally  good  tempered.  The  majority  of  the  instances  of 
unprovoked  attacks,  says  Hornaday,  have  been  probably  by  mother  bears 
who  fancied  their  cubs  in  danger — even  those  bears  which  ate  up  the  chil- 
dren in  Elijah's  day  were  "she-bears. "i  When  a  bear  is  aroused  it  ia 
exceedingly  formidable.  It  deals  killing  blows  with  one  of  its  paws, 
having  been  known  to  kill  a  buffalo  with  one  blow.  It  does  not  hug  its 
victims  to  death.  The  grizzly  flees  from  man  unless  cornered.  In  cold, 
snowy  countries,  where  bears  are  unable  to  obtain  food  they  pass  the  winter 
in  a  sort  of  sleep,  living  upon  their  fat  stored  up  in  the  fall,  but  they  do  not 
become  torpid,  as  the  cold-blooded  animals  do.  In  some  species  the  males, 
which  hibernate  singly,  come  out  from  time  to  time.  They  do  not  hibernate 
in  the  troj^ics  nor  in  captivity,  leading  us  to  believe  that  the  winter  sleep 
of  the  north  is  only  another  adaptation  to  environment. 

According  to  Beddard,  the  polar  bear  hunts  "by  scent  rather  than  sight 
or  hearing,  both  of  which  senses  seem  to  be  somewhat  dull."  All  American 
bears,  except  the  polar  bear,  change  their  color,  being  darkest  in  late  summer 
and  lightest  in  spring.  There  are  a  number  of  well-marked  types  of  bears, 
eight  of  which  live  in  Asia  and  Europe,  and  four,  the  polar  bear,  the  brown 
bear,  the  grizzly,  and  the  black,  live  in  America.  One  group  is  found  all 
around  the  North  Pole  and  another  group  in  South  America.  The  oil,  fat, 
and  fur  of  bears  are  used. 

Not  until  the  Pliocene  in  the  Old  World  and  later  in  the  New  did  the  true 
bears  (  Ursus)  appear.  So  this  family,  which  is  highly  specialized  in  some 
features  and  very  primitive  in  others,  is  among  the  youngest  of  the  Car- 
nivora. 

The  fur-bearers  {Mustel'idce)  are  blood-thirsty  robbers,  often  killing 
many  times  what  they  can  consume,  seemingly  from  a  spirit  of  mere  wan- 
tonness. "The  testimony  of  the  rocks,"  says  Ingersoll,  "shows  that  this 
family  is  either  an  ancient  branch  from  the  civet  stock,  or  that  it  has  sprung 
from  the  same  root."  The  genus  Lutra  is  widely  distributed.  It  includes 
the  otter.  The  front  and  hind  feet  are  webbed,  and  the  claws  on  the  hind 
feet  flattened  and  nail-like. 

The  North  American  otter  is  still  occasionally  found  "in  Florida,  Carolina, 

1 II  Kings  ii,  24. 


360  BRANCH   CHORDATA 

Canadian  provinces,  in  a  few  localities  in  the  Rocky  Mountain  region,  and 
from  British  Columbia  to  central  Alaska."  The  home  for  the  rearing  of  the 
two  young  is  a  burrow  in  the  bank  of  a  stream.  The  sea  otter  (Latax  lutris) 
feeds  largely  on  sea-urchins  and  shell-fish,  and  its  molars  are  flattened  and 
the  tubercles  very  blunt,  for  crushing  the  shells.  This  animal  has  been  so 
much  hunted  for  its  exceedingly  valuable  fur  that  it  has  changed  its  habit 
of  feeding  upon  the  shore  to  hunting  in  the  deeper  waters,  and  makes  its 
bed  on  floating  masses  of  kelp.  It  is  rare  except  in  Alaska,  and  is  one  of  the 
wildest  and  wariest  of  animals.  At  present  the  otters  are  among  the  most 
valuable  of  all  fur-bearing  animals,  a  single  skin  of  the  sea  otter  having  been 
sold  in  London  for  £250,  or  about  $1250. 

The  badger  (Meles)  has  naked  soles  and  the  claws  of  the  fore  feet  are 
much  longer  than  those  of  the  hind  feet.  The  true  badger  of  Europe  and 
eastward  is  nocturnal,  omnivorous,  and  burrowing,  loving  the  woods. 
The  South  American  badger  resembles  the  European  one,  but  is  smaller. 
Its  three  or  four  young  are  born  naked.  Its  body,  which  is  about  2  feet 
long,  is  broad  and  flat,  and  its  legs  very  short.  It  has  a  suHen,  savage  dis- 
position. It  feeds  on  ground  squirrels  and  prairie-dogs.  It  ranges  over  the 
Great  Plains,  the  Rocky  Mountains  and  westward,  and  from  Mexico  to 
Alaska.  In  the  United  States  it  is  more  or  less  active  all  winter,  being  able 
to  find  food,  but  farther  north  it  is  forced  to  spend  the  severest  portion  of 
the  winter  in  semitorpidity.  There  are  a  number  of  species  in  Asia.  The 
Teledu  {Myd'aus  melictes),  of  Java  and  Sumatra,  is  said  to  rival  the  skunk  in 
the  odor  of  its  secretion. 

The  skunks  {Mephi'tis),  of  which  there  are  nine  species,  are  widely  dis- 
tributed in  America.  They  are  distinguished  by  their  jet  black  color, 
variously  banded,  with  longitudinal  bands  or  spots  of  pure  white,  making 
them  conspicuous.  This  is  surely  a  fine  example  of  warning  colors,  for  both 
man  and  beasts  are  well  aware  of  the  strong  offensive  odor  of  the  anal  se- 
cretions which  can  be  ejected  for  a  distance  of  several  feet.  Despite  this 
efficient  means  of  defense  the  skunk  is  sometimes  devoured  by  the  puma, 
the  harpy  eagle,  and  the  great  horned  owl.  It  is  destructive  of  poultry, 
but  is  a  destroyer  of  myriads  of  noxious  insects  and  mice.  The  fur  is  ex- 
tensively used,  first  being  dyed. 

The  marten  and  weasel  tribe  is  distinguished  by  a  long  slender  body, 
short  legs,  and  cat  paws.  These  small,  agile  creatures  have  valuable 
fur.  The  group  includes  the  Siberian  sable,  the  North  European  marten, 
and  the  Canadian  pine  marten.  The  marten  is  18  inches  long,  with  a  rather 
bushy  tail  of  7  or  8  inches.  It  is  brown  above,  lighter  below,  and  varies 
according  to  the  age,  sex,  and  season.  "The  winter  fur  is  thick,  soft,  1§ 
inches  deep,  of  the  richest  hue,  and  has  scattered  through  it  coarse,  black 
hairs  which  the  furrier  pulls  out."  The  six  or  eight  young  are  born  high  up 
in  a  hollow  tree  or  in  a  rocky  crevice.  The  Canadian  marten  is  not  a  poultry 
thief  nor  wanton  murderer",  but  kills  what  it  wants  to  eat  of  squirrels,  hares, 
and  grouse,  trailing  them  with  the  nose  to  the  ground  like  a  hound.  Few 
animals  will  oat  the  marten  unless  extremely  hungry. 

The  mink  is  small  and  of  a  chocolate  or  yellowish-brown  color,  with  a 
round  hairy  tail.  It  is  scattered  throughout  North  America  along  the  banks 
of  streams.  It  feeds  chiefly  upon  birds  and  is  a  "wanton  murderer."  The 
black-footed  ferret  is  nearly  always  found  in  the  prairie-dog  villages.  The 
English  ferret  is  simply  a  domesticated  variety  of  the  polecat  {Puto'ritis 
fetidus)  .1 

1  Beddard,  p.  436. 


MAMMALIA  361 

The  weasel  is  the  smallest  animal  of  the  group.  The  body  is  very  loug 
and  "no  thicker  than  a  man's  thumb."  Its  fur  changes  from  brown  in 
summer  to  white  in  winter.  This  winter  fur  is  known  as  ermine,  and  comes 
from  Alaska,  Canada,  La;pland,  Russia,  and  iSiboria.  It  is  used  not  only 
for  ladies'  garments,  but  for  the  robes  and  crowns  of  kings.  The  smallest 
of  all  Carnivores  is  Putorius  rixosus,  of  northwestern  Canada.  It  is  only 
6  inches  in  total  length  and  brown  to  the  tip  of  its  tail.  In  all  other  species 
the  end  of  the  tail  is  l)lack.  The  change  of  color  to  white  helps  to  retain  the 
body  heat,  and  helps  also  to  conceal  the  animal  from  its  enemies  and  its 
prey.'  Poulton  believes  that  the  cause  of  this  change  of  color  is  the  lower 
temperature  acting  upon  the  skin,  and  that  existing  dark  hairs  Ix'conu'  white 
at  the  tips.  Others  maintain  that  in  cold  regions  the  summer  pelage  is  re- 
placed in  winter  by  hairs  which  come  in  wholly  white,  while  in  warm  regions 
the  new  winter  coat  is  brown.  However,  Doctor  Coues  says  he  has  seen 
many  autumnal  skins  which  were  white  at  the  roots  and  dark  at  the  tips. 
In  any  case,  natural  selection  has  preserved  those  individuals  having  the 
power  of  changing  the  color  of  the  fur  until  this  character  is  now  general. 

The  dog  family  (Canidce)  is  universally  distributed,  with  the  exception 
of  New  Zealand.  These  animals  have  a  simple,  cyhndric  cecum  and  usually 
five  toes.  Perhaps  the  most  striking  feature  of  the  family  is  the  bladder- 
like inflation  of  the  auditory  bulla,  that  part  of  the  skull  containing  the 
internal  ear.  This  apparatus  and  sense  is  perfected  in  the  dogs.  Many  of 
this  family  are  familiar. 

There  are  several  genera,  but  the  principal  one  is  Catds,  including  our 
dogs,  wolves,  foxes,  and  jackals.  Huxley  divides  them  into  fox-like  and 
wolf-like  dogs.  The  foxes  are  more  active  than  the  wolves,  with  a  "broad 
skull,  sharper  muzzle,  larger  ears,  a  more  bushy  tail,  and,  usually,  longer 
fur."  They  are  notably  clever  and  quick  witted,  and  often  show  skill  in 
meeting  new  situations  made  by  the  advent  of  man. 

The  typical  fox  is  the  common  red  fox  {Vulpes  fulvus),  of  wide  distri- 
bution. Our  American  form  varies  from  the  typical  yellowish  red,  darkest 
on  the  back  and  shoulders,  to  a  very  bright  or  very  pale  yellowish  red. 
It  may  have  the  markings  on  the  spine  and  withers  very  dark  and  distinct, 
making  it  a  "cross-fox,"  or  be  totally  black  with  a  white-tipped  tail,  or  black 
with  the  tips  of  most  of  the  hairs  white,  giving  the  fur  a  frosted  or  silver 
appearance.  Either  of  the  last  two  cases  is  called  "silver  fox."  These  rare 
and  valuable  variations  may  occur  in  the  same  litter  with  the  normally 
reddish  ones.  Foxes  feed  upon  ground  birds  and  their  eggs,  rodents,  frogs, 
lizards,  insects,  and  fruits.  They  may  be  caught  by  raj)id  chase,  l^y  digging 
the  burrowing  forms  out  of  the  ground — for  the  fox  is  nat  urally  a  burrower — 
by  stealthily  creeping  up  on  them,  or  by  lying  apparently  dead  until  the  vic- 
tim approaches,  and  then  pouncing  upon  it .  \\\\\\v  it  ( loes  sometimes  raid  the 
hen  coops,  the  fox  does  good  service  in  destroying  rats,  mice,  and  gophers. 
It  sometimes  stores  its  surplus  food.  Its  enemies  are  all  the  large  cats  and 
wolves,  as  well  as  man  and  dogs  in  the  so-called  sport  of  fox  chasing.  The 
red  fox  has  a  litter  of  seven  or  eight  young;  the  southern  gray  fox,  of  four  or 
five.  The  gray  fox  is  smaller.  It  climbs  trees  to  get  the  "sour  grapes"  and 
persimmons,  but  it  cannot  adapt  itself  to  the  prairies.  The  arctic  fox 
{Vulpes  lagopus)  furnishes  another  example  of  color  variation  under  the 
influence  of  a  different  climate.  In  the  extreme  north  it  is  snow  white  all 
the  year  round.  A  little  farther  south  it  is  brown,  with  the  under  parts 
lighter  in  summer  and  white  in  winter,  while  in  the  southern  part  of  its 
range,  as  in  the  Aleutian  Island  and  parts  of  Greenland,  it  is  most  often  bluish 


302  BRANCH    CHOKDATA 

or  slate  gray.  That  these  are  not  different  species  is  proved  by  the  fact  that 
occasionally  one  or  two  "blue  foxes"  occur  in  the  litter  where  all  the  rest 
become  white;  for  all  the  young  are  blue.  The  arctic  fox  is  valued  for  its 
fur.  The  blue  variety,  being  less  abundant,  is  worth  twice  that  of  the  white. 
Commercial  companies  are,  therefore,  making  attempts  to  breed  these  foxes 
on  the  islands  of  the  Alaska  coast.  In  the  extreme  north  the  arctic  fox 
stores  its  food  in  summer  for  the  long,  desolate  winter.  There  are  a  number 
of  other  species  of  foxes. 

The  wolf-like  dogs  include  the  dof^s,  jackals,  and  wolves.  Domestic  dogs 
of  to-day  comprise  about  two  hundred  l)n'('ds.  They  are  owned  l)v  natives 
of  all  countries  except  the  South  Sea  Islands.  They  have  been  associated 
with  mail  for  thousands  of  years,  their  remains  having  been  found  in  Danish 
kitchen-middens,  in  the  Swiss  lake-dwellings,  and  in  the  remains  of  the 
Bronze  Age  in  Europe  generally.  It  is  only  since  the  invention  of  firearms 
that  hunting  with  dogs  has  become  general,  as  stealth  was  necessary  to  the 
successful  hunter  and  the  dog  might  frighten  the  game.  It  might  have  been 
used  in  running  down  such  animals  as  the  deer,  but  it  seems  from  obtainable 
evidence  that  it  was  used  for  the  protection  of  the  camp,  to  watch  while  the 
master  slept,  and  to  give  the  alarm  if  beast  or  man  came  near;  or  it  served  as 
food  in  time  of  necessity.  Authorities  vary  in  their  opinion  as  to  what  stock 
gave  rise  to  the  domestic  races.  "  The  jackal,  bunasu,  and  the  Indian  wolf 
have  been  suggested  as  ancestors.  It  is  probable  there  has  been  much 
mixture  and  that  different  wild  types  have  been  selected  by  man  in  various 
countries. "1  The  inteUigence  of  dogs  and  their  ability  to  learn  by  training 
are  well  known  and  utihzed  by  breeders  and  dealers. 

There  are  many  species  of  African  and  Oriental  jackals.  Some  feed 
chiefly  on  carrion,  but  also  commit  de])redations  uixm  the  hen  roosts  and 
farmyards;  others  live  upon  figs,  and  others  chiefl}-  upon  fruits.  Their  cry 
is  a  long  howl,  ending  in  a  series  of  short  yeli)s.  Anderson  says  "they  often 
congregate  near  one's  tent  and  make  the  night  hideous  with  their  howls." 

The  wolf  of  the  present  time  is  distributed  over  most  of  Europe,  northern 
Asia,  and  North  America,  wherever  a  rough  country  affords  it  shelter. 

Hornaday  says  "there  is  no  depth  of  meanness,  treachery,  or  cruelty  to 
which  they  do  not  cheerfully  descend.  They  are  the  only  animals  on  earth 
which  make  a  regular  practice  of  killing  and  eating  their  companions  and 
devouring  their  own  dead.  But  in  the  face  of  foes  capable  of  defense  even 
gray  wolves  are  rank  cowards,  and,  unless  cornered  in  a  den,  will  not  stop 
to  fight  for  their  own  cubs."  The  five  or  more  sooty  brown  whelps  are  bom 
in  a  cave  (which  is  often  dug  by  the  mother)  early  in  May,  but  usually  only 
two  or  three  survive.  In  winter  wolves  form  a  pack  to  assist  each  other  in 
attacking  the  prey.  Travellers  througli  inf(>stcd  rc^gions  have  been  boldly 
pursued  and  killed  by  them.  Th(>  prolonged  de(>p-chested  bass  howl,  which 
"multiplies  itself  by  its  rapid  eelu)ing  luitil  one  wolf  sounds  Hke  a  dozen," 
is  not  brok(>n  into  a  bark  like  that  of  the  coyote.  The  timber  or  gray  wolf 
{(\niix  ocn'doilalifi)  is  very  much  like  the  European  (C  lupus).  It  can  adapt 
itself  to  almost  any  situation,  being  at  home  in  the  timbered  regions  or  on  the 
treeless  prairies  of  the  West,  in  the  evergreen  or  on  the  treeless  prairies  of 
the  West,  in  the  evergreen  forests  of  British  Columbia,  and  on  the  desolate 
barren  ground  of  arctic  America.  Its  winter  coat  is  long  and  shaggy,  a,nd 
varies  from  the  standard  gray  (black  and  white  mixed)  to  black  in  Florida 
and  rufous  in  Texas,  while  in  the  North  it  varies  from  black  to  the  predomi- 
nating white  color  of  arctic  animals. 

1  Beddard,  p.  423. 


MAMMALIA 


363 


The  coyote  (C.  latrans)  (Fig.  292)of  the  western  plains  is  one-third  smaller 
than  the  gray  wolf,  and  carries  the  tail  low,  as  behts  a  coward,  while  that  of 
the  wolf  points  above  the  horizon.  The  cry  is  a  dog-like  yelp,  half  howl, 
half  bark.  They  feed  upon  prairie-dogs,  ground  squirrels,  sage  grouse,  and 
rabbits,  and,  probably,  sheep  and  pigs.  They  are  not  dangerous  to  man. 
The  five  to  seven  puppies  are  born  in  deep  holes  or  washouts  in  the  banks  of 
streams  in  May. 

The  cat  family  (Fe'lidoe)  includes  lions,  tigers,  cats,  and  the  hunting  leop- 
ards. The  distribution  is  worldwide,  with  the  exception  of  Australia  and  a 
good  deal  of  the  Australian  region.     In  genus  Felis  the  claws  are  retractile. 

The  lion  {F.  leo)  differs  from  all  others  by  the  possession  of  a  mane  by 
the  adult  male.  The  largest  lions  come  from  south  Africa.  The  adult  is 
uniform  pale  tawnish  or  yellowish  gray.  The  young  is  spotted.  It  inhab- 
its Africa,  India,  parts  of  western  Asia,  and  formerly  ranged  into  Europe. 


Fig.  292.— Coyote.     (Circular  63,  Biologic  Survey,  U.  S.  D.  A.,  April,  1908.) 


It  is  mainly  nocturnal  in  its  habits,  though  it  often  feeds  in  daytime  or  at 
dusk,  as  the  animals  go  to  the  spring  for  water.  It  feeds  on  anything  it 
can  capture,  or  even  on  carrion.  The  male  may  hunt  alone,  while  his  mate 
cares  for  the  two  to  five  whelps  or  cubs  in  some  dense  cover,  bringing  the 
food  to  his  mate.  It  is  said,  however,  that  the  males  eat  at  the  first  table, 
leaving  the  rest  of  the  family  to  take  what  is  left.  When  the  cubs  are  okl 
enough  the  mother  joins  in  the  search  for  prey,  which  is  usually  obtainefl 
by  "stalking,"  that  is,  by  stealthily  creeping  up  through  the  tall  grass  and 
leaping  upon  it,  striking  a  fell  blow,  and  clutching  it  with  claws  and  teeth. 
Failing  in  this,  they  sometimes  give  chase.  Lions  cannot  climb  trees. 
"The  choice  of  mate  seems  to  lie  with  the  female,"  says  Ingersoll,  "and 
the  continuance  of  the  union  appears  to  depend  on  the  power  of  the  lion  to 
hold  his  fickle  spouse  to  her  allegiance."  She  tries  to  flirt  with  every 
new  male,  but  her  mate  bounds  between  her  and  the  intruder  and  then 


364  BRANCH    CHORDATA 

ensues  a  fierce  struggle  for  possession  unless  the  intruder  slinks  away. 
The  female  fawns  upon  the  contiueror,  wliiehever  he  may  be.  There  is 
some,  though  insufficient,  evidence,  that  the  male  is  sometimes  a  polyg- 
amist.     Lions  will  live  for  thirty  or  forty  years  and  breed  well  in  captivity. 

The  tiger  {F.  tigris)  is  about  the  same  size  as  the  lion,  the  female  being 
12  or  15  inches  shorter  than  the  male.  He  is  more  quick,  sly,  subtle,  and 
cunning.  The  tiger  is  exclusively  Asiatic,  ranging  northward,  even  into  icy 
Siberia.  Tigers  are  creatures  of  the  mountains  rather  than  the  open  plains. 
The  northern  ones  are  adapted  to  the  cold  climate  by  longer  and  closer  fur. 
Tigers  can  climb  trees  and  can  swim  considerably.  Naturally,  they  hunt  in 
the  evening  or  night,  but  extreme  hunger  may  drive  them  to  hunt  in  day- 
time. The  Malays  and  Hindus  hold  them  in  superstitious  terror  and  oppose 
their  destruction. 

The  leopard  or  panther  {F.  pardm)  is  both  African  and  Asiatic.  It 
varies  from  almost  black  to  a  tawny  color.  It  is  spotted  with  small  rosettes 
or  rings  of  black  surrounding  spots  of  light  or  tawny  color.  Some  of  the 
spots  are  solid  black.  It  is  as  ferocious  as  a  tiger,  but  sly  and  cautious,  and 
far  lighter  and  more  active.  It  can  climb  a  tree  like  a  cat.  It  necessarily 
preys  upon  smaller  animals  than  do  lions  and  tigers,  playing  havoc  with 
poultry,  sheep,  goats,  dogs,  wild  birds,  monkeys,  and  wild  pigs.  Carrion 
also  furnishes  it  food.  Its  cry  is  a  "  harsh,  measured,  coughing  roar."  The 
snow  leopard  or  ounce  {F.  uncia)  is  a  beautiful  creature,  white,  with  larger 
black  spots.     It  is  confined  to  the  highlands  of  central  Asia. 

The  jaguar  {F.  onca)  is  the  largest  and  handsomest  of  the  American  cats. 
The  head  is  large  and  the  tail  short.  It  has  a  golden-yellow  coat,  marked  on 
the  back  and  sides  with  large  black  rosettes,  between  which  run  the  narrow 
lines  of  yellow  ground  color.  The  spots  on  the  legs,  head,  and  under  parts 
are  solid  black.  It  is  found  in  South  America,  Mexico,  and  as  far  north  as 
Texas.  Hornaday  believes  that  it  has  the  strongest  jaws  of  any  member  of 
the  cat  family.  It  is  fierce,  powerful,  and  dangerous,  but  is  afraid  of  man. 
It  also  climbs  trees. 

The  puma  {F.  concolor)  is  found  in  "all  the  great  western  mountain-ranges 
and  in  many  tracts  of  the  bad  lands  of  Wyoming  and  Montana,  in  British 
Columbia,  in  the  Adirondacks  and  Florida,"  and  south  to  Patagonia. 
Hornaday  says  that  although  the  puma  has  been  known  "to  follow  belated 
hunters  out  of  curiosity,  this  animal  is  less  to  be  dreaded  than  a  savage  dog." 
It  sometimes  screams  like  a  terrified  woman  or  boy;  it  always  flees  from  man 
if  there  is  a  way  of  escape.     It  is  a  thin,  tall  animal  of  a  brownish  drab  color. 

The  lynxes  of  North  America  are  "short-tailed,  heavily  furred,  tree- 
climbing  cats,"  distributed  over  nearly  all  the  wild  portions  of  the  country 
north  of  Mexico,  whether  forests,  mountains,  plains,  canyons,  or  even 
deserts.  They  are  neither  courageous  nor  pugnacious  unless  cornered. 
The  Canada  lynx  (L.  canadensis)  has  a  long  pencil  of  stiff  black  hairs  rising 
from  the  tip  of  each  ear.  It  has  large,  hairy  paws,  and  is  a  good  climber. 
It  swims  well,  but  runs  rather  poorly  on  land.  A  full-grown  one  weighs 
22  pounds.  There  are  two  young.  The  Bay  lynx,  or  wild-cat,  is  usually  a 
mixture  of  rusty  red,  gray,  and  l)lackish  brown,  with  red  prevailing.  It 
is  found  in  both  the  East  and  West  and  in  Texas.  No  lynxes  are  found  in 
the  lowlands  of  tropical  or  South  America. 

The  domestic  cat,  says  Beddard,  is  regarded  as  the  descendant  of  the 
eastern  F.  caffra  or  the  closely  allied  F.  maniculata,  or  from  both  and  from 
their  interbreeding  with  the  wild-cat  of  Europe,  for  many  species  of  cats, 
even  the  lion  and  tiger,  it  is  said,  will  interbreed.  Whatever  was  the  source, 
they  have  been  cro,ssed  and  interbred  with  many  varieties  before  reaching 


MAMMALIA  365 

the  "  house  cat  "  of  to-day.  The  domestication  of  the  cat  is  very  remote. 
A  tablet  dating  from  1600  b.  c.  has  on  it  the  representation  of  a  cat. 
"  Rows  of  skilfully  wrapped  mummies  of  cats  in  richly  adorned  cases"  may 
be  seen  at  Cairo,  showing  that  ancient  Egyptians  must  have  held  them 
in  reverence. 

The  hunting  leopard  {Cyncelu'rus  jubatus),  of  Africa,  India,  Persia,  and 
Turkestan,  has  longer  legs  and  less  retractile  claws  than  the  true  cats.  In 
India  it  has  been  trained  for  ages  to  capture  game  for  its  masters. 

The  civets  ( Viver'ridve)  are  comparatively  small  animals,  with  usually 
five  digits  and  with  non-retractile  or  very  incompletely  retractile  claws. 
There  is  usually  a  scent  gland,  which  is  the  source  of  the  civet  perfume. 

The  Tracker  ( Hrrpcx'tcs  ichncu'mon),  or  "Pharaoh's  rat,"  is  the  size  of  a 
cat  with  dark  <iray  color.  It  destroys  the  eggs  of  crocodiles,  hzards,  and 
snakes.      H.  gn'.^'ius  (Mongoose)  destroys  the  Cobra. 

The  genus  hyena  (Hyot'idcr)  comprises  three  living  species.  The  body 
is  bulky,  the  legs  strong,  the  head  big  and  dog-hke,  and  the  jaws  strong. 
They  are  nocturnal  scavengers,  though  sometimes  seizing  small  animals. 
They  are  found  in  Europe,  Asia,  and  Africa,  but  not  in  America. 

Geologic  Distribution. — "The  first  Carnivores  appear  in  the 
order  Creodon'ta,  plantigrade  forms  of  slightly  differentiated 
dentition  (no  carnassials) ;  they  present  marked  resemblances  to 
marsupials,  insectivores,  as  well  as  to  the  Condylar'thra,  the  an- 
cestral ungulates."^  There  is  a  long  gap,  both  in  time  and 
structure,  between  the  few  Eocene  carnivores  and  their  supposed 
ancestors  among  the  Creodonts,  which  are  generalized  types 
as  hinted  above.  In  the  late  Miocene  the  present  groups 
of  Carnivora  become  more  or  less  distinct  by  the  intermediate 
"  stock  forms  becoming  extinct." 

Use  to  Man. — Hundreds  of  lion  skins  are  sold  annually, 
thousands  of  wild-cat  skins,  and  more  than  a  million  skins  of  the 
common  cat  are  made  into  cheap  furs. 

The  aquatic  carnivora  (Pinnipe'dia)  include  the  seals,  sea- 
lions,  ancl  walruses.  They  have  acquired  a  somewhat  fish-like 
form.  The  limbs  are  flattened  into  broad  flippers,  the  five 
long  toes  are  webbed,  and  the  nails  are  often  rudimentary. 
Molars  and  premolars  are  similar  (carnassial  absent). 

The  northern  fur  seal  {Ota'ria  tirsina)  and  the  Patagonian  maned  sea-lion 
(O.jubata)  belong  to  the  genus  Otaria,  which  is  mainly  antarctic.  The  har- 
bor seal  is  the  common  form  along  the  Atlantic  Coast.  There  is  a  colony 
of  sea-lions  on  the  Pacific.  In  -the  fur  seals  there  is  a  dense,  soft  under  fur. 
The  Alaska  seal  has  its  summer  residence  and  breeding  grounds  in  one  or 
two  islands  of  the  Behring  Sea.  In  winter  they  are  absent  from  these 
islands,  and  "their  whereabouts  is  a  matter  of  much  speculation."  They 
live  in  groups,  consisting  of  a  single  old  male  and  five  to  twenty  females. 
The  young  males  a  year  or  two  old  herd  by  themselves,  maturing  at  the 

1  Hcrtwig. 


306  BRAN'CH    CHOKDATA 

age  of  six.  The  females  mature  younger.  The  males  are  six  or  eight  times 
as  large  as  the  females.  The  rivalry  between  the  males  is  intense.  In  the 
fighting,  great  strength  of  neck  and  jaw  is  used.  The  fur  seal  industry  rep- 
resents many  millions  of  dollars. ^ 

The  walrus  family  ( Trichech'idve)  belongs  to  the  aquatic  carnivores.  The 
walrus  is  arctic  and  circumpolar.  It  is  characterized  by  the  enormous 
canines  of  the  upper  jaw,  which  form  tusks  sometimes  30  inches  long.  The 
walrus  is  from  10  to  12  feet  long,  and,  though  it  can  move  about  on  land,  it 
is  very  ungainly.  The  hair  is  short  and  scanty.  As  in  the  true  seals,  there 
are  no  external  ears.     The  flesh,  fat,  and  hide  are  much  used  in  the  North. 

The  true  seals  {Pho'cidce)  have  the  nostrils  in  a  dorsal  position  and  have 
no  external  ears.  The  hind  limbs  are  bound  up  with  the  tail  and  are  useless 
on  land.  The  largest  is  the  elephant  seal,  about  20  feet  long.  The  male 
has  a  proboscis  of  about  15  inches.  This  seal  is  mild  and  inoffensive  except 
when  enraged,  and,  of  course,  during  the  breeding  season.  The  whole 
animal  is  invested  in  a  mass  of  blubber  which  is  as  thick  as  that  in  a  whale. 

Order  IX.  Insectiv'ora. — These  arc  small,  plantigrade,  long- 
snouted,  chiefly  nocturnal  mammals,  which  feed  on  insects  and 
earthworms.  The  eyes  are  small  or  hidden  by  fur.  The  clav- 
icle is  usually  present;  the  cecum,  absent  or  minute.  As  a  rule, 
there  are  five  digits.  All  of  this  order  are  provided  with  sharp 
teeth.  The  front  teeth  in  both  jaws  are  inclined  outward,  being 
less  adapted  for  seizing  the  prey.  The  brain  is  of  simple  struc- 
ture, the  hemispheres  usually  smooth. 

Hedgehogs  are  covered  with  spines,  but  they  are  not  barbed  as  in  the 
porcupine,  and  they  are  firmly  attached.  Hedgehogs  feed  upon  insects, 
chickens,  young  game  birds,  and  even  vipers.  They  are  less  than  a  foot  in 
length,  about  the  size  of  a  big  rat.  They  disappear  in  hot  weather,  and  come 
out  in  rainy  weather.  They  hibernate  in  winter.  E.  europoeus  defends  it- 
self by  rolling  up  into  a  ball,  with  its  head  tucked  between  its  fore  feet  and 
the  hind  feet  drawn  up  close  together,  thus  presenting,  on  all  sides,  its  sharp 
spines  to  its  enemies,  few  of  which  will  attack  the  hedgehog.  Hedgehogs 
are  not  found  in  the  Western  Hemisphere.  Their  voice  is  described  as  a 
sound  between  a  grunt  and  a  squeak. 

The  shrews  (Soric'idce)  (Fig.  293)  are  small,  nocturnal,  f ur-covei  ed  in- 
sectivores,  which  are  often  mistaken  for  mice,  but  the  teeth  show  they  are 
not  rodents.  They  are  of  wide  distribution,  but  are  not  found  in  Australia 
nor  in  South  America.  Several  species  are  found  in  the  United  States. 
S.  personatus  is  chestnut  brown,  with  large  ears  and  short  tail.  They  are 
thinly  covered  with  hair.  Their  length  is  2f  inches;  the  tail,  1  inch.  They 
are  found  from  Massachusetts  to  Alaska.  Tiie  water  shrew  {S.  palustris) 
is  the  largest  of  our  shrews,  measuring  6  inches,  with  the  tail  2h  inches  long. 
The  lesser  shrews  of  Great  Britain  are  burrowing,  nocturnal  animals,  and 
secrete  a  disagreeable  odor  for  protection.  They  are  among  the  smallest 
of  all  mammals. 

1  See  Hornaday,  or  Jordan's  "Report  of  the  Fur  Seal  Investigation," 
1896-97. 


MAMMALIA 


367 


The  moles  {Tal'pidce)  are  subterranean  animals,  with  bioad  front  feet 
and  vestigial  eyes.  The  common  prairie  mole  {Scalops  aquaticus  machrinus) 
(Fig.  294)  is  well  known  by  its  habit  of  burrowing  in  gardens  for  earthworms 
and  grubs.  It  eats  also  the  roots  of  vegetables.  Its  powerful  front  limbs 
are  clawed  for  digging.  Its  hind  limbs  are  weak,  the  tail  short,  and  the  nose 
pointed.     The  star-nosed  mole  of  the  eastern  United  States  {Condylu'ra 


Fig.  29o. — Common  shrew.     (After  Coues.) 


cristola)  has  the  tip  of  its  snout  encircled  with  fleshy  projections.  Talpa  is 
an  Old  World  form.  The  Russian  Desman  {Myog'ale  moscata)  lives  in 
burrows  in  the  banks  of  streams.  It  feeds  on  fresh-water  insects  and  larva?. 
An  Oriental  insectivore  is  an  aberrant  form.  It  is  much  larger  than  most 
of  the  order  and  has  an  integumentary  membrane,  connecting  the  neck  with 
the  fore  limb,  the  fore  limb  with  the  hind  limb  and  the  hind  limb  with  the 
tail. 


Fig.  294  — Common  mole  [hidlop^  aquaticus),  Lmn.     (Aftei  Coues.) 


Geographic  Distribution. — This  order  is  represented  in  every 
region  except  South  America  and  AustraUa.  The  moles  are 
confined  to  the  temperate  regions  of  the  Northern  Hemisphere. 
Hedgehogs  are  not  found  in  the  Western  Hemisphere  nor  in 

Austraha. 


368 


BRANCH  CHORDATA 


Geologic  Distribution. — In  North  America  they  date  back  to 
the  Eocene  Period.  The  Miocene  Paloeoerina' ceus  differs  so 
little  from  the  existing  genus,  Erina'ceus,  that  the  latter  may  be 
called  "  one  of  the  oldest  living  genera  of  mammals." 

Use  to  Man. — Many  mammals  of  this  order  have  fine  soft 
fur.  They  are  also  of  value  as  insect  destroyers.  A  single  mole 
is  said  to  devour  twenty  thousand  insects  annually. 

Order  X.  Chiroptera. — The  bats  have  many  points  of  resem- 
blance and  structure  with  both  lemurs  and  insectivores.  But 
they  are  distinguishable  from  all  other  mammals  by  their  power 


Fig.  295. — Skeleton  of  ipleropm:  <S7,  Slrniuiu;  (7,  clavicle;  Sc,  scapula; 
H,  humerus;  R,  radius;  U,  ulna;  D,  thumb;  J  I,  ilium;  P,  pubis;  Js, 
ischium;  Fe,  femur;  T,  tibia;  F,  fibula.     (After  Owen.) 


of  zigzag  flight.  "  The  wings  "  (Fig.  295)  consist  of  an  integu- 
mental  membrane,  supported  by  the  digits  (two  to  five),  which 
are  greatly  elongated  and  are  folded  together  like  the  ribs  of  an 
umbrella  when  the  wings  are  folded.  A  membrane  between  the 
hind  legs  and  tail,  when  present,  is  used  for  steering. 

The  expanse  of  wing,  compared  with  that  of  the  body,  is 
greater  than  that  of  most  birds,  but  the  muscles  are  weaker. 
The  first  digit,  or  thumb,  is  short,  free,  and  strongly  clawed, 
"  and  sometimes  a  sucker,  by  which  l)ats  scramble  about  rocks 
and  trees,  recalls  the  similar  organ  in  that  primitive  lizard-like 


MAMMALIA  369 

bird,  the  Archceopterix."  The  bones  of  this  order  are  slender 
and  hght.  The  skull  and  teeth  present  many  extraordinary 
variations.  The  radius  is  long  and  curved,  the  ulna  is  rudiment- 
ary, and  the  knee  is  directed  backward.  The  sternum  is  keeled 
for  the  attachment  of  the  pectoral  muscles,  the  chief  muscles  of 
flight.  The  ribs  are  flat  and  sometimes  ankylosed  together  by 
their  margins.  The  fibula  is  rarely  fully  developed.  The  hind 
limbs  are  small  and  serve  as  a  means  of  hanging  the  body  head 
downward  in  rest  or  sleep,  but  are  almost  useless  for  walking. 
The  skull  is  almost  as  large  as  the  chest.  The  ears  are  sometimes 
much  longer  than  the  head.  The  nostrils  are  wide  and  are  often 
surrounded  by  highh'  complicated  sensitive  membranes,  which 
sometimes  give  the  face  a  comical  or  even  hideous  expression. 
These  are  often  more  strongly  developed  in  the  male.  The  cheek 
teeth  of  the  insectivorous  bats  terminate  in  sharp  points,  and 
are  designed  for  cutting  to  pieces  the  hard  parts  of  hard-shelled 
insects.  The  fruit-eating  bats  have  molars  with  rather  smooth 
crowns,  while  the  vampires  (Fig.  296,  p.  371)  have  molars 
with  scissor-edges  and  large  canine  teeth  with  sharp,  cutting 
edges.  The  eyes  are  minute  except  in  the  fox  Ijats.  The  wing 
membranes  are  sensitive,  containing  intricate  network  of  blood- 
vessels, nerves,  and  "  end  organs,"  and  thus,  by  the  aid  of  their 
sensitive  wings  and  sensitive  membranes  on  the  face,  bats  are 
enabled  to  fly  without  touching  bodies  in  their  way,  though  they 
be  in  utter  darkness  or  when  their  eyes  are  so  minute  and  fur- 
buried  that  they  could  not  detect  the  intruding  object.  The 
cerebral  hemispheres  are  smooth  and  do  not  extend  over  the  cere- 
bellum. Bats  are  small  and  nocturnal  and  generally  insectiv- 
orous, generally  feeding  on  the  wing,  thus  they  are  beneficial. 
Some  are  fruit-eating,  and  others,  as  the  vampires  of  South 
America,  are  blood-sucking,  attacking  warm-blooded  animals, 
and  will  even  withdraw  a  quantity  of  blood  from  a  sleeping  man. 
There  is  nothing  whatever  to  fear  from  the  ba+s  of  the  United 
States,  for  their  claws  and  teeth  are  weak.  The  fur  is  usually 
brown  or  gray,  "  but  a  few  Oriental  species  are  mottled  or  varie- 
gated with  orange,  bright  yellow  and  black,"  as  is  shown  by 
the  "  painted  "  ])at  of  Ceylon.  This  bat  hides  by  day  in  the 
folded  leaf  of  a  plantain,  and  when  disturbed,  looks  more  like  a 
butterfly  than  a  bat.     Mr.  Swinhoe,  a  naturalist  long  residing 


370  BRANCH    CHORDATA 

in  China/  says  that  these  colors  are  highly  protective,  for  the 
brilliant  bat  inhabiting  Formosa  resorts  to  the  longan  tree. 
This  evergreen  tree  always  has  some  portion  of  its  foliage  decay- 
ing, making  these  dying  leaves  orange  and  black,  while  the  fruit 
is  reddish  yellow.  Thus  the  orange  and  black  bat,  suspended 
from  the  branches,  is  concealed  from  its  enemies  by  its  protect- 
ive resemblance.  Owing  to  their  nocturnal  habits  very  little 
is  known  of  the  activities  of  bats.  "  We  know  that  in  the  winter 
some  of  our  species  live  in  caves  in  a  semidormant  condition," 
and  Dr.  Hart  Merriam  has  proved  that  some  species  do  migrate 
in  fall  and  spring.  All  bats  living  within  the  snow  limit  of  the 
Temperate  Zone  must  either  migrate  or  hibernate,  for  the  fruit- 
eating  bats  could  find  no  food,  and  the  delicate  wings  of  the 
vampire,  which  might  find  food,  would  be  frozen  stiff  in  zero 
weather,  so  the  latter  are  chiefly  tropical.  Bats  usually  inhabit 
caves,  a  million  sometimes  hibernating  in  one  cave.  The  thick 
layer  of  guano  on  the  floor  of  the  cave  may  represent  the  deposit 
of  centuries.  Bat  guano  is  a  valuable  fertilizer.  In  warm 
countries  bats  live  in  hollow  trees.  The  cry  is  a  shrill  squeak. 
They  are  widely  distributed,  being  found  on  islands  where  there 
are  no  other  mammals.  The  occurrence  of  the  same  genus  of 
bats  in  India  and  Madagascar  has  led  some  to  believe  that  there 
must  have  been  at  one  time  some  connection  between  these 
countries,  as  these  slow-flying  creatures  could  hardly  have 
traversed  these  vast  stretches  of  ocean  by  their  power  of  flight 
alone.2  However,  Hornaday  tells  of  a  British  long-eared  bat 
which  was  found  clinging  to  the  rail  of  an  Atlantic  steamer  30 
miles  from  land,  with  no  breeze  going  from  the  land. 

Bats  are  divided  into  two  groups:  the  large  diurnal  (Meg'a- 
chirop'tera),  or  fruit-eating  bats,  and  the  nocturnal  (Mi'cro- 
chirop'tera),  or  insect-eating  bats.  "Many  bats  have  a  strong 
musky  odor,  due  to  secretion  of  certain  glands  in  the  skin." — 
Weysse. 

Megachiroptera. — The  ordinary  fruit  bats  or  fox  bats  number  about  forty 
species.  The  fur  is  fox  red,  the  muzzle  long  and  pointed.  The  eyes  are 
big  and  the  ears  upright,  giving  them  a  fox-like  appearance.  They  live  in 
colonies  of  from  five  to  fifty.  Hornaday  killed  some  having  40  inches 
spread  of  wings.  He  says  "of  all  creatures  that  fly,  none  are  so  uncanny 
when  outlined  against  the  sky  as  the  big  black-winged,  half-naked  flying 
fox  (bats).  They  suggest  demons  and  calamities."  The  fruit-growers  of 
1  Ingersoll,  p.  63.  '  Beddard,  p.  525. 


MAMMALIA  371 

California,  being  fearful  of  their  introduction  into  the  United  States,  have 
secured  a  law  prohibiting  their  importation  even  into  zoological  gardens. 
In  the  Ethiopian  region  this  family  is  represented  by  the  large,  grotesque, 
hammer-headed  bat  {Epomoph'orus).  Its  head,  particularly  the  muzzle,  is 
enlarged,  giving  it  a  resemblance,  in  profile,  to  the  head  of  a  moose.  The 
larger  fruit  bats  are  eaten  by  natives  of  their  countries  and  even  relished  by 
white  men.  They  make  affectionate  pets,  but  it  would  seem  strange,  weird 
ones. 

Microchiroptera  includes  five  families.  Here  belong  the  leaf-nosed  bats 
already  mentioned,  the  "bonneted  bats,"  and  the  naked  bats,  the  vampires 
(Fig.  296),  and  the  common  smaller  bats.  The  naked  bats  of  Borneo  have 
thick,  leathery,  elastic  skin.  A  scent  gland  for  defense  is  situated  between 
two  folds  about  the  neck.  The  most  remarkable  thing  is  the  mammary 
pouch  under  each  arm — a  wide  pouch  of  rubber-like  skin  in  wnich  the  young 
are  carried  until  able  to  fly.  The  mammary  gland  is  in  the  lower  portion  of 
the  pouch. 


Fig,  296. — Head  of  Phyllos'tonia  {\'cn)tpyrus)  spectruni.     (Claus.) 

Of  the  vampires  or  blood-suckers,  the  javelin  bat  {Phijlos'toma  hastatum) 
bites  horses,  cattle,  and  even  sleeping  man.  The  sharp-edged,  dagger-like 
teeth  make  a  small  round  hole  in  the  skin,  from  which  the  vampire  draws 
the  blood  by  mouth  suction.  The  blood  sometimes  flows  freely  after  the 
bat  has  left  its  victim,  but  there  is  no  poison  attending  a  wound.  The 
digestive  organs  of  the  vani])ires  are  extremely  modified,  these  bats  living 
upon  predigested  liciuid  food.  The  gullet  is  too  narrow  for  any  solid  food  to 
pass  throujili  and  the  stoninch  is  intestine-like. 

The  common  bats  (  I  '<  s/n  rUlion'idce)  range  overall  parts  of  the  world,  and 
number  oxer  two  liuiKU'cd  sj>ecies.  Most  of  the  bats  of  the  United  States, 
about  eighteen  species,  belong  to  this  family.  They  are  very  common 
along  the  Atlantic  coast  a,nd  there  are  several  species  along  the  Pacific. 
The  commonest  is  the  little  red  bat,  which  flies  about  in  the  early  twilight. 
It  is  constantly  on  the  wing  from  sunset  until  dark.  In  its  flight  it  can  turn 
abruptly  and  with  great  accuracy.  It  is  remarkable  that  it  can  turn  and 
double  so  quickly  and  dart  in  all  possible  directions  without  striking  any- 
thing. Thegraj^bat  of  the  northeastern  United  Slates  and  Canada  and  the 
big-eared  bat  of  the  South  Atlantic  coast  are  members  of  t  his  family.  The 
North  American  bats  never  make  any  nests.  The  little  bats  are  born  in 
crannies,  and,  from  the  first,  cling  about  the  mother's  neck  when  she 
chases  the  "numberless  little  flying  things  of  the  dusk.  When  there  are 
twins,  the  male  takes  his  share  of  the  responsibility." 


372  BRANCH    CHORDATA 

Geologic  Distribution. — Bats  appear  for  the  first  time  in  the 
Eocene  Epoch,  according  to  the  records  of  the  rocks. ^ 

Order  XI.  Prima'tes. — This  order  includes  all  animals  with 
hands  and  hand-like  feet.  With  but  a  few  exceptions  the 
members  of  this  order  inhabit  the  tropics.  Except  in  man,  they 
reach  their  highest  development  near  the  equator.  Hornaday 
says  that  there  is  no  human  being  of  sound  mind  to  whom  the 
human  likeness  of  the  lower  Primates  does  not  appeal.  They 
are,  at  any  rate,  very  much  like  man  in  their  structural  develop- 
ment. As  a  rule,  they  have  five  fingers  and  toes,  each  covered 
at  the  tip  by  a  flat  nail.  The  inner  finger  or  toe,  or  both,  are 
opposable,  making  the  hand,  and  often  the  foot,  a  grasping  organ. 
The  feet  are  plantigrade.  The  limbs  are  quite  free  from  the 
body,  as  compared  with  those  of  other  chordates.  The  skull  of 
the  Anthropoi'dea  is  characterized  by  the  bony  partition  between 
the  orbital  and  temporal  vacuities.  The  stomach  is  simple. 
The  cecum  is  always  present  and  sometimes  large.  They  are 
chiefly  arljoreal,  except  terrestrial  man. 

The  sub-order  Lemuroi'dea  includes  the  aye-aye,  tarsier,  and 
the  lemurs.  The  head  lacks  the  human-like  expression,  being 
more  like  a  fox,  with  a  sharp  muzzle.  There  are  no  cheek 
pouches.  The  tail,  which  is  never  prehensile,  varies  from  none, 
in  Loris,  to  the  long  and  bushy  tail  of  the  "  aye-aye."  The 
thumb  and  great  toe  are  well  developed  and  the  second  toe  has 
a  sharp  nail  unlike  the  flat  nail  of  the  other  digits.  The  brain 
case  is  small  and  the  temporal  and  orbital  fossae  are  in  com- 
munication. The  placenta  is  non-deciduate.  The  vermiform 
appendix  is  never  present  and  the  cecum  varies  in  length. 
They  are  now  found  only  in  Madagascar,  tropical  Africa,  and  the 
Orient.  In  the  Tertiary  Period  the  ancestors  of  these  animals 
were  scattered  all  over  the  globe. 

The  lemurs  {Lemur'idoe)  have  round  heads  with  fox-like  muzzles,  small 
ears,  and  a  long  tail  (Fig.  297).  The  wooly  fur,  which  is  often  beautifully 
tinted,  is  soft  and  thick.  In  size  they  vary  from  that  of  the  squirrel  to  that 
of  the  cat.  They  are  omnivorous,  and,  as  a  rule,  diurnal  or  crepuscular. 
They  are  found  in  Madagascar.  In  trees  they  run  about  on  all  fours,  but  on 
the  ground  they  walk  erect  on  their  liind  h^s.  The  one  or  two  young  are 
carried  about  by  the  mother  as  they  cliiiji  to  lier  breasts,  or,  later,  ride  upon 
her  back.     One  of  the  most  interesting  is  the  ring-tailed  lemur,  which 

1  Scott's  "  Geology,"  p.  506. 


MAMMALIA 


373 


scrambles  over  the  rocks,  its  leathery  palms  being  furrowed  with  sucker- 
like grooves,  enabling  it  to  go  where  man  cannot.  The  ruffed  or  black  and 
white  lemur  is  perhajis  t  lio  most  beautiful.  It  is  the  size  of  a  large  house  cat, 
has  a  long  tail,  ami  i-  cIdI  lud  in  long,  soft,  silky,  fine  fur.  The  mouse  lemurs, 
dwarf  lemurs,  and  fat -l ailed  lemurs  estivate  during  the  hot  and  dry  seasons, 
curling  up  in  their  nests,  just  as  northern  animals  do  in  hibernation. 
"They  go  in  fat,  subsist  by  absorption  of  this  stored  tissue,  and  come  out 
thin  and  weak"  at  the  approach  of  the  rainy  season.  Lemurs  are  all  per- 
fectly harmless,  but  their  weird  actions,  big  eyes,  and  loud  cries  have  led  to 
their  being  reverenced  and  feared  by  the  superstitious  natives. 

The  female  aye-aye  constructs  a 
globular  nest  in  a  tree  for  the  rearing 
of  her  single  offspring. 

Sub-order  Anthropoidea  differs 
from  the  lemurs  in  having  the 
mammary  glands  always  tho- 
racic, the  orbital  and  temporal 
fossse  separated  by  bone.  The 
cerebral  hemispheres  are  highly 
developed,  almost  or  quite  con- 
cealing the  cerebellum.  There 
are  over  two  hundred  tropical 
and  subtropical  species. 

American  monkeys  (Platyrrhi'na) 
differ  from  the  Old  World  forms  in 
having  the  nostrils  directed  downward 
and  separated  by  a  broad  septum. 
As  a  rule,  they  are  also  smaller  and 
have  but  thirty-two  teeth.  The  tails 
are  usually  long  and  prehensile.  No 
American  form  has  cheek  pouches. 
Most  of  them  are  arboreal.  All 
American  monkeys  are  small,  varying 
in  size  from  that  of  young  kittens  or 
chipmunks  to  20  inches  long.  They 
are  hairy  or  woolly.  One  baby  mon- 
key is  born  to  each  female  each  year. 

The  marmosets  are  lowest  in  the  scale  of  development,  indeed,  they 
sometimes  look  very  little  like  monkeys.  They  range  from  southern 
Mexico  to  southern  Brazil.  They  are  sniall,  delicate  creatures,  with  hair- 
less faces,  large,  bright  eyes,  and  long  tails.  In  some  species  the  long  silky 
hair  stands  up  on  the  head  like  a  white  ruff.  The  digits  are,  for  the  most 
part,  clawed,  the  great  toe  only  bearing  a  flat  nail.  They  are  arboreal,  but 
the  tails  are  not  prehensile. 

The  second  family  of  American  monkeys  {Ceb'idoe)  is  distinguished  from 
the  marmosets  by  thirty-six  teeth,  and  by  the  generally  long  and  prehensile 
tail,  which  is  naked  on  the  under  side  of  the  end. 


Fig.  297. —Otolicn us  galago  of  Af- 
rica.    (From  Vogt  and  Specht.) 


374 


BRANCH    CHORDATA 


The  Saki  monkeys  {Pithe'cia)  of  tropical  South  America  east  of  the  Andes 
have  long,  bushy,  non-prehensile  tails,  and,  sometimes,  a  long,  black  chin 
beard. 

The  squirrel  monkeys  {Sai'miri)  are  little  creatures  with  a  long  head,  the 
occiput  projecting.  The  proportions  of  the  cranium,  as  compared  with  the 
face,  are  greater  than  in  other  monkeys  or  in  man.  They  are  gregarious  and 
arboreal,  feeding  upon  insects,  small  birds,  and  eggs. 

The  howlers  are  the  most  hideous  looking  of  the  American  monkeys  and 
have  the  least  intelligence.  The  brain  is  less  convoluted  than  that  of  the 
At'eles.     Their  howl,  made  to  intimidate  enemies,  can  be  heard  two  miles. 


Fig.  298. — Spider  monkey.     (American  Museum  of  Natural  History.) 


The  natives  hate  the  howlers  and  kill  them  for  food,  selling  the  hide  to  white 
traders.     The  hair  is  twisted  into  cordage. 

The  spider  monkey  (Ateles)  (Fig.  29S)  is  the  most  typically  arboreal 
of  American  monkeys.  With  its  prehensile  tail  held  erect  over  its  head,  it 
"feels"  for  a  place  to  grasp,  which  it  does  by  wrapping  the  end  of  its  long 
slender  tail  tightly  around  the  branch.  It  then  swings  itself  far  across 
toward  another  limb,  which  it  grasps  with  its  thumbless  hands  by  hooking 
them  around  the  limb  and  thus  suspending  its  body.  "They  have  a  very 
uncanny  look  and  can  come  as  near  tying  themselves  into  a  knot  as  any  liv- 
ing mammal  can."     They  are  weak  and  cowardly.     The  Mexican  spider 


MAMMALIA  375 

monkey  is  the  most  northern  one  in  America,  sometimes  coming  up  to 
latitude  32°. 

Perhaps  the  most  typical  of  this  family  is  the  genus  Cebus  of  twenty 
species,  ranging  from  Costa  Rica  to  Paraguay.  The  common  monkey 
of  the  organ-grinder  belongs  to  this  genus.  The  thumb  is  well  developed. 
The  color  is  usually  dull  brown,  but  one  is  brick  red  and  others  have  white 
about  the  shoulders.  They  are  gregarious.  Contran  tot  he  licucral  belief 
that  they  are  strictly  herbivorous,  they  are  very  fond  of  cati  r])illars. 

"No  monkeys  ascend  high  in  the  Andes  nor  reach  the  west  coast ,  and  none 
are  found  south  of  the  forests  of  Brazil  or  north  of  south  cenlial  Mexico. 
Fossil  remains  of  monkeys  are  rare  everywhere,  and  known  in  tlic  New  World 
only  in  the  Santa  Cruz  Alioccnc  formations  of  Patagonia;  and  they  show 
no  more  kinship  with  tlic  <)lil  World  t\pcs  than  do  tlie  existing  species."^ 

Old  World  monkeys  (('nturrhi' ikd  iia\c  the  nostrils  close  together  and 
directed  downward.  There  are  open  cheek  pouches  and  but  thirt  y-t  wo  teeth. 
The  tails  are  non-prehensile  or  even  absent.  Often  there  are  hard  patches 
of  hairless,  bright-colored  skin  (ischial  collosities)  upon  the  havuiches. 
Catarrhine  monkeys  are  larger  and  more  intelligent  than  the  Platyrrhine 
forms.  These  distinctions  are  ancient,  "since  no  fossil  remains  of  mon- 
keys at  all  intermediate  have  so  far  been  discovered,  another  evidence  of 
the  very  early  time  at  which  South  America  becanic  isolated." 

Macaques  and  baboons  (family  Cer'copithec'uhr  )  contains  eight  or  nine 
genera  divided  into  two  subfamilies.  The  first  (Cri-'cnplllHci'tKr)  consists 
of  rather  large  monkeys  represented  by  macaques  and  halxions.  Tiiey  have 
cheek  pouches  in  which  to  store  the  food.  All  the  nuuiKincs  hut  one  are 
Asiatic.  They  are  from  13  inches  to  3  feet  long,  the  male  being  larger  than 
the  female,  with  larger  canine  teeth.  They  are  gregarious,  noisy,  and  active, 
"scrambling  about  rocks,  and  some  swim  and  dive  well."  In  some  parts  of 
India  they  damage  gardens.  Their  dog-like  teeth  and  strong  nails  are  able 
to  inflict  severe  wounds.  As  examples,  the  bonnet  monkey,  the  Gibraltar 
ape,  and  the  pig-tailed  monkey  may  be  mentioned.  The  latter  is  trained 
by  the  natives  to  climb  the  cocoanut-palm  tree  and  to  select  and  throw  down 
the  ripe  cocoanuts. 

The  baboons  {Cynoceph' alus)  are  found  in  Africa  and  Arabia.  The 
African  forms  vary  in  size  from  that  of  a  spaniel  to  that  of  a  mastiff. 
Their  stout  limbs  are  about  equal,  the  nose  and  head  are  dog-like,  and  the 
canine  teeth  long  and  sharp.  They  are  the  fiercest  of  all  Primates.  It  is 
said  that  even  a  hungry  lion  will  not  attack  a  baboon.  The  great  ischial 
collosities  are  strikingly  colored,  adding  to  the  ugliness  caused  by  overhang- 
ing eyebrows,  small  eyes,  ferocious  disposition,  and  filthy  habits.  It  is 
said  these  collosities  attract  the  kite  bird,  which  mistakes  t  Iicm  for  raw  meat, 
and  the  baboon  makes  a  meal  of  the  bird.  The  color  is  l)lackisli  or  a  green- 
ish or  yellowish  gray,  grizzled  by  each  hair  being  ringed  with  various  colors. 
The  Gelada  has  a  black  body  and  a  brown  mane,  with  a  gray  chest.  It  looks 
like  a  small  lion  with  a  baboon's  hands  and  feet.  Baboons  like  the  open 
country  and  the  rocky  hills  ;rnd  deserts.     They  go  in  troops. 

The  second  sub-family  (Semnopitheci'nae)  includes  guerezas,  thelangurs, 
or  Asiatic  holy  apes,  and  (he  Bornean  genus  Nasalis.  They  are  slender 
apes  with  no  che(>k  jiourhes  and  have  a  sacculated  stomach. 

The  anthropoid  apes  iSiini'idce),  though  chiefly  arboreal,  walk  erect  or 
semi-erect  when  tiiey  come  to  the  ground.  Their  hands  and  feet  are  fitted 
for  a  half-arboreal,  half-terrestrial  life.     When  they  put  their  hands  to  the 

1  Ingersoll,  p.  37. 


37G 


BRANCH    CHORDATA 


firoiiiid  to  aid  in  walking  tlicy  rcsi,  ..,,.m  the  hack  of  the  knuckles.  Cheek 
])i)ucli('s  and  tail  arc  lackiiifi  and  the  hair  is  more  scaiiiy  than  in  the  baboons. 
These  entirely  Old  World  forms  have  a  verniiforni  a|)|)endix. 

The  gibbons  {IJ i/lnh'dlcs),  slender,  nionkey-iike  Indo-Mahiyan  forms, 
stand  at  the  base  of  the  series.  They  are  tlie  smallest  an<l  most  arboreal 
and  their  arms  are  the  lon^;est  of  any  of  the  firouj),  beinti  lon^  enough 
to  reach  the  ground  even  when  standing  erect.  The  ranines  are  large  in 
hot  h  sexes  and  t  he  jaws  and  nose  are  prolonged.  The  lirain  is  simpler  than 
in  t  he  higher  forms.  One  of  the  most  remarkable  habits  is  tluur  tleseending 
flight  t  hrough  the  trees,  though  they  never  come  to  the  ground.  They  leai) 
incredible  distances,  says  Hornaday,  catch  and  swing  with  their  hands,  catch 
again  with  their  feet,  turning  again,  and  so  on,  by  a  series  of  revolutions 
almost  as  fast  as  the  flight  of  a  bird.  The  largest  is  the  Sumatran  Siamang, 
which  stands  3  feet  tall  and  is  shining  black.  The  gray  gibbons  are  very 
timid,  but  show  strong  affection  for  their  young  and  great  courage  in  their 
defense. 


299.     Comparison  of  skeletons  of  pri 
chimpanzee;  4,  gorill 


ites:    1,  Cibbon;  2,  orang;  3, 
"),  man. 


The  brown  orang-utan  lives  in  Horneo  and  Sumatra,  wholly  in  the 
tree-tops,  coming  to  the  ground  only  for  water.  On  the  ground  it  moves 
slowly  and  swings  its  body  along  between  its  arms  like  a  pair  of  crutches. 
In  the  trees,  too  heavy  for  leaping,  they  swing  underneath  the  branches  with 
their  long  arms,  "grasping  a  limb  with  their  hook-like  hands,  and  swinging 
underneath  to  the  next  hold,  and  so  on,  at  great  s]khm1."'  It  subsists  upon 
wikl  fruits,  fleshy  leaves,  and  shoots  of  the  screw  pine.  It  is  shy  and  uncer- 
tain if  captured.  When  young  it  is  easily  tamed;  when  grown,  wild  and 
ferocious.  Hornaday  says  "in  1901  the  zoological  i)ark  contained  four 
orangs,  all  of  which  were" taught  to  wear  clothes,  sit  in  chairs  at  table,  eat 
with  fork  and  spoon,  drink  from  cups  and  bottles,  and  ])erform  many  human- 
like actions  without  nc  rvousiu^ss  in  the  ])resence  of  two  thousand  visitors. 
Elach  of  the  orangs  learned  its  i)art  in  about  two  weeks'  training,  and  at  the 

1  Ingersoll. 


MAMMALIA  377 

dinner  table  acted  with  gravity  and  decorum."  In  (iaptivity  y(jung  orangs 
are  affectionate  as  children  and  are  fond  of  their  human  friends.  At  night 
the  wild  orang  makes  a  nest  to  sleep  upon  by  breaking  off  leafy  branches 
and  laying  them  crosswise  in  the  forked  top  of  a  sapling,  where  it  lies  fiat 
u])on  its  back,  grasjjs  the  branch  firmly  in  each  hand  and  foot,  and  is  rocked 
to  .sleep  in  the  tree-top. 

Tlu'  chimpanzee  (Fiji;.  300)  luis  u  "  bruin,  face,  ears,  and  hands 
more  man-like  tlian  those  of  any  other  ape."  Its  face,  ears, 
hands,  and  feet  an;  naked.     It  lias  a  large  brain  and  a  higher 


Fig.  300. —The chimpanzee,  variety  Tshego.  (From  Hrehm's  "Thierlebcn.") 

intellect  than  any  of  the  Primat>(^s  below  man.  It  is  bright  and 
cheerful  and,  having  a  good  memory,  is  easily  taught.  The 
young  are  affectionate,  but  the  old  males  are  dangerous.  There 
are  at  least  two  sp(^cies.  They  are  natives  of  Afri(;a.  Mated 
pairs  seem  to  remain  together  i)ermanently,  and  missionaries, 
when  they  tried  to  tea(;h  that  ])olygamy  was  wrong,  have  been 
told  by  the  natives  "  that  they  (lid  not  wish  to  ])e  lik(>  apes." 
They  spend  much  time  hiding  in  thickets  in  family  groups, 
sometimes  gathering  in  such  numb(>rs  as  to  do  considerable 
damage  to  young  bananas.     They  are  crepuscular.     They  show 


378 


BRANCH  CHORDATA 


great  affection  for  their  families,  the  father  often  taking  the  baby 
from  the  mother  and  carrying  it,  especially  in  dangerous  places, 
and  they  seek  to  assist  one  another  when  hurt  or  in  trouble. 
They  seem  to  delight  in  noise,  uttering  loud  shrieks  and  howls, 
and  drumming  with  sticks  on  resonant  logs.  This  is  the  only 
employment  of  an  instrument  or  tool,  and,  in  itself,  shows  a  wide 
difference  between  the  chimpanzee  and  the  lowest  human  savage. 


Fig.  301. — Gorilla  engt  )ia      (\  ogt    uid  bpcchl  ) 


A  rude  platform  of  branches  is  built  for  the  family  bed,  the 
father,  perhaps,  sleeping  curled  up  in  a  crotch  of  the  tree  be- 
neath it. 

The  Gorillas. — Both  in  kind  and  number  "the  bones  below  the 
skull  are  the  same  in  the  skeletons  of  man  and  the  gorilla. 
They  differ  only  in  their  proportions  "  (Fig.  299,  4).  The  widest 
differences  are  in  the  skulls.  In  the  gorilla  the  high  forehead 
and  intellectual  faculties  so  characteristic  of  man  are  entirely 


MAMMALIA  379 

wanting,  indicating  a  low  order  of  intelligence.  "  The  long  and 
powerful  canine  teeth  are  alone  sufficient  to  proclaim  the  savage 
wild  beast."  The  gorilla  is  not  teachable  like  the  chimpanzee, 
but  is  sulky  and  ferocious.  The  gorilla  is  the  only  ape  that  walks 
erect.  Its  arms  are  relatively  short  and  its  legs  long.  Its 
hands  reach  a  little  below  the  knees  when  standing  erect.  It 
has  big  feet  and  a  pronounced  heel.  The  digits  are  webbed.^ 
The  brain  is  larger  than  that  of  the  chimpanzee,  but  so  is  the 
body.  The  great  similarity  of  structure  to  that  of  the  human 
body  is  due  largely  to  the  plantigrade  walk  and  the  terrestrial 
life.  The  gorilla  is  more  primitive  than  the  chimpanzee  and, 
therefore,  nearer  to  the  common  ancestral  stock.  It  is  found  in 
a  small  area  in  West  Africa  on  the  equator,  and  between  the 
Gaboon  and  Congo  Rivers.  Hornaday  declares  that  if  the  head 
of  a  chimpanzee  were  placed  on  the  shoulders  of  a  gorilla,  we 
should  have  the  "  missing  link,"  and  that  if  the  missing  link 
is  ever  found,  it  will  be  in  the  "  Tertiary  deposits  of  the  fertile 
uplands  that  lie  between  the  gloomy  equatorial  forests  of  the 
black  apes  and  the  bushmen  of  South  Africa." 

Man. — Fossil  remains  of  a  man-like  ape,  Anthropopithe'cus 
erectus,  have  been  fomid  in  the  upper  Pliocene  of  Java.  It  is 
generally  thought  that  these  fragments  belong  to  an  exceed- 
ingly large  gibbon-like  animal  having  an  enormous  cranial 
cavity  and  a  brain  nearly  equal  in  size  to  that  of  some  of  the 
savage  races  of  man  to-day.  There  is  no  doubt  that  man 
lived  on  the  earth  at  the  beginning  of  the  Pleistocene  times, 
and  it  is  thought  by  many  anthropologists  that  he  lived  in  the 
latter  part  of  the  Tertiary  Period,  though  this  has  not  been 
satisfactorily  proved. 

The  family  Hominidce  contains  but  a  single  genus.  Homo, 
and  one  species,  H.  sapiens.  The  different  varieties  of  this 
species  are  now  generally  classified  in  three  great  groups: 
the  Ethiopian,  of  Africa;  the  Mongolian,  of  Asia;  and  the  Cau- 
casian, of  Europe.  Man  is  distinguished  from  other  primates 
by  a  less  development  of  hair  on  the  body,  by  the  erect  walk, 
and  by  the  consequent  modification  of  the  hind  limbs  and  feet 
(he  is  a  true  biped).  The  face  does  not  project  so  much  as 
that  of  the  anthropoid  apes.  The  skull  of  man  is  a  smooth, 
1  Beddard,  p.  572. 


380  BRANCH    CHORDATA 

rounded  case,  while  that  of  the  a])es  is  smaller  and  deeply  ridged 
and  contains  a  smaller  brain.  Man's  outstretched  hand  does 
not  reach  the  knee  and  the  thuml)  is  much  more  useful.  The 
hallux  (great  toe)  is  not  opposable.  There  are  no  laryngeal 
pouches.  "  The  minute  diverticula,  the  ventricles  of  Morgagni, 
alone  remain  to  testify  of  a  former  howling  apparatus  in  the 
ancestors  of  man."^ 

Man  has  the  power  of  articulate  speech  and  the  faculty  of 
reason.  As  to  whether  this  vast  difference  in  reason  be  one 
of  kind  or  degree,  psychologists  disagree,  but  all  concede  that 
the  reasoning  power  of  man  is  far  in  advance  of  that  of  any 
other  animal. 

Man's  superiority  over  animals  lies  in  his  highly  developed 
powers  of  abstract  thought,  reason,  and  will.  Through  these 
powers  he  is  able  to  adapt  himself  to  his  environment,  make  a 
new  environment,  or  migrate  to  one  better  suited  to  his  needs. 
He  can  control  the  lower  forms  of  ^nimal  life  and  modify  them 
by  artificial  selection  and  ])reeding  to  satisfy  his  wants.  From 
them  he  procures  clothing,  leather,  food,  ornaments,  weapons, 
fertilizer  for  his  land,  and  materials  used  in  his  houses.  He 
uses  them  as  beasts  of  burden  or  as  means  of  travel.  Through 
undue  use  or  slaughter  he  has  caused  the  extinction  of  various 
species. 

The  student  has  missed  the  greatest  value  of  the  study  of 
zoology  if  he  has  not  discovered  that  the  great  underlying 
principles  which  permeate  and  control  all  animal  life  from  the 
lowest  to  the  highest  forms  necessarily  apply  also  to  the  life, 
development,  and  history  of  mankind.  Descent  with  adaptive 
modifications  is  amply  illustrated  in  the  descendants  of  one 
man  during  his  lifetime.  The  influence  of  environment, 
growth  and  decay,  heredity,  variation,  adaptation,  the  survi- 
val of  those  best  adapted  to  conditions  in  the  physical  or  the 
business  world,  the  strengthening  of  powers  of  body  or  mind 
by  use,  the  degeneration  of  powers  by  dependence  upon  others, 
the  sacrifice  of  the  parent  for  the  offspring  everywhere  seen  in 
nature,  or  the  triumph  of  altruism  over  egoism  in  the  service 
of  one's  family  or  his  fellow-men — these  are  some  of  the  bio- 
logic principles  directly  applicable  to  man. 
1  Beddard,  p.  589. 


MAMMALIA 


381 


Classification. — 

Order. 
I.  Monotrem'ata. 
II.  Marsupia'lia. 

III.  Edenta'ta. 

IV.  Sire'nia. 
V.  Ceta'cea. 

VI.  Ungula'ta.o 
VII.  Roden'tia. 
VIII.  Carniv'ora. 
IX.  Insectiv'ora. 
X.  Chirop'tera. 
XI.  Prima'tes. 


Examples. 
Duckbill,  Spiny  Ant-eater 
Kangaroo,  Opossum. 
Ant-eater,  Armadillo. 
Manatee,  Dugong. 
Whales,  Porpoises. 
Cattle,  Sheep,  Deer,  Horses 
Rabbits,  Squirrels,  Prairie- 
Cats,  Dogs. 
Moles,  Shrews. 
Bats. 
Apes,  Monkeys,  Man. 


THEORIES   OF   DEVELOPMENT 

Origin  of  Life. — Many  scientists  to-day  advocate  that  life 
is  the  action  of  chemical  and  physical  forces  in  connection  with 
a  peculiar  substance  called  protoplasm.  But  no  one  has  yet 
been  able  to  explain  all  the  phenomena  of  life  by  means  of  these 
forces.  Until  this  is  done,  we  must  believe  that  life  from  life 
is  the  universal  rule,  or  that  no  living  organism  originates  except 
from  some  pre-existing  living  form. 

Protoplasm  is  the  physical  basis  of  all  life,  both  plant  and 
animal,  and  without  this  complex  substance  life  cannot  exist. 
It  is  a  protein  which  is  known  only  as  a  product  of  living  sub- 
stances.^ It  is  chemically  and  physically  unstable,  but  it  is 
impossible  to  obtain  a  satisfactory  chemical  analysis  since  the 
dead  material  differs  from  the  living  protoplasm  both  in  its 
power  and  structure. 

There  is  little  direct  proof  of  the  character  of  life  in  the 
Archaean  Era,  but  it  must  have  been  marine.  Since  plants 
usually  feed  upon  inorganic  matter  and  animals  cannot  manu- 
facture organic  compounds  from  inorganic  ones,  and  as  plant 
life  is  thus  a  necessity  for  the  existence  of  animal  life,  it  is 
thought  that  plant  life  may  have  been  first.  However,  the 
view  that  plant  and  animal  forms  originated  side  by  side  and 
have  developed  along  diverging  lines  is  comm.on. 

Since  the  simplest  form  of  life  to-day  consists  of  a  single  cell, 
it  is  believed  that  primitive  life  began  as  a  single  cell. 

The  Cell  Theory. — Cells  were  first  described  by  Hooke,  an 
Englishman,  in  1665,  and  were  so  named  from  the  resemblance 
of  the  compartments  in  the  structure  of  a  piece  of  cork  to  the 
cells  in  a  monastery.  Schleiden,  in  1838,  showed  that  plants 
were  composed  of  cells,  and  in  1839  Schwann  discovered  the 
same  general  fact  concerning  the  bodies  of  animals,  thus  re- 
vealing the  common  plan  of  organization  of  plants  and  animals. 

The  cell  theory  involves:  (1)  that  all  organisms  are  made  up 
iMcFarland's  "Biology." 


CELL   DIVISION    OR    MITOSIS  383 

of  single  cells  or  combinations  of  cells;  (2)  that  all  organisms 
begin  life  as  a  single  cell,  giving  rise  in  metazoans  to  a  body  of 
more  or  less  complexity,  and  (3)  that  the  function  of  this  com- 
plex (multicellular)  organism  may  be  expressed  in  terms  of  the 
activities  of  the  individual  cells  of  which  it  is  composed.  The 
third  proposition  may  need  some  modification.  "It  was 
through  the  cell  theory  that  Kolliker,  Remak,  Nageli,  and 
Hofmeister  opened  the  way  to  an  understanding  of  the  nature  of 
embryologic  development,  and  the  law  of  genetic  continuity 
lying  at  the  basis  of  inheritance.  It  was  the  cell  theory  again 
which,  in  the  hands  of  Goodsir,  Virchow,  and  Max  Schultze, 
inaugurated  a  new  era  in  the  history  of  physiology  and  pathol- 
ogy, by  showing  that  all  the  various  functions  of  the  body,  in 
health  and  in  disease,  are  but  the  outward  expressions  of  cell 
activities.  And  at  a  still  later  day  it  was  through  the  cell 
theory  that  Hertwig,  Fol,  Van  Beneden,  and  Strasburger  solved 
the  long-standing  riddle  of  the  fertilization  of  the  egg  and  the 
mechanism  of  hereditary  transmission.  No  other  biologic 
generalization,  save  only  the  theory  of  organic  evolution,  has 
brought  so  many  apparently  diverse  phenomena  under  a  com- 
mon point  of  view,  or  has  accomplished  more  for  the  unification 
of  knowledge.  The  cell  theory  must,  therefore,  be  placed  be- 
side the  evolution  theory  as  one  of  the  foundation  stones  of 
modern  biolog\."^ 

Cell  Structure. — In  the  typical  cell  are  found  the  following 
parts:  (1)  the  cell  wall;  (2)  the  cytoplasm,  or  cell  substance, 
which  includes  the  plasma  (that  is,  the  living  protoplasm  around 
the  nucleus)  and  the  chylema,  or  "cell-sap";  (3)  a  nucleus  which 
is  usually  inclosed  by  a  delicate  membrane,  and  which  contains 
chromatin  and  achromatin  fibers  and  one  or  more  nucleoli,  and 
(4)  one  or  two  centrosomes  or  attraction  spheres. 

Cell  Division  or  Mitosis. — The  centrosome  divides  into  two 
parts,  which  gradually  separate,  and  each  of  which  becomes  the 
center  of  a  system  of  fine  achromatin  fibers  radiating  about  it. 
A  spindle  of  achromatin  fibers  is  also  extended  from  one  centro- 
some to  the  other.  At  the  same  time  the  chromatin  granules 
scattered  throughout  the  nucleus  are  arranged  into  a  continu- 
ous thread  or  skein  of  closely  contorted  filaments.  The  nuclear 
1  Wilson,  "The  Cell." 


384  THEORIES    OF    DEVELOPMENT 

membrane  generally  disintegrates  and  the  chromatin  thread  is 
broken  up  into  U-shaped  fragments  (chromosomes).  These 
U-shaped  chromosomes  are  arranged  as  the  equatorial  plate 
half-way  between  the  centrosqmes  and  across  the  axis  of  the 
spindle.  Either  before  or  after  the  formation  of  the  equatorial 
plate  the  chromosomes  split  longitudinally,  so  that  each  part 
contains  an  equal  amount  of  the  chromatin.  The  chromosomes 
now  move  along  the  spindle  (or  its  fibers  contract),  so  that  one- 
half  of  each  original  chromosome  is  drawn  to  one  centrosome 
and  the  other  half  to  the  other  centrosome.  These  chromo- 
somes, with  their  apexes  pointing  toward  the  center,  are  now 
arranged  about  their  respective  centrosomes.  The  protoplasm 
of  the  general  cell  becomes  constricted  in  the  center,  each  group 
of  chromatin  loops  rearranges  itself  into  a  nucleus  like  that  of 
the  mother  cell,  and  an  investing  membrane  becomes  ap- 
parent. A  furrow  appears  on  the  surface  of  the  protoplasm  and 
gradually  deepens  until  the  protoplasm  is  divided  into  two  equal 
segments,  each  containing  its  own  nucleus  and  centrosome  and 
being  a  complete  daughter-cell. 

Maturation. — Metazoans  usually  reproduce  by  means  of 
fertilized  eggs  or  ova.  Egg  cells  vary  in  size  from  less  than  ^io 
to  about  T¥o  inch  in  diameter.  By  this  is  meant  the  minute 
germ  cell  without  the  enormous  amount  of  nutritive  material 
which  usually  accompanies  it. 

Before  the  process  of  fertilization  takes  place  (about  the 
time  of  the  entrance  of  the  spermatozoon,  which,  however, 
takes  no  part  in  the  process)  the  ovum  undergoes  a  process  of 
maturation,  in  which  one-half  of  the  number  of  chromosomes  is 
thrown  off.  A  spindle-shaped  structure  is  formed  from  minute 
fibers  in  the  cytoplasm.  The  centrosomes,  one  at  each  pole  of 
the  spindle,  seem  to  control  its  formation  and  activities.  This 
spindle  draws  from  the  egg  nucleus  a  definite  number  of  chro- 
mosomes which  are  arranged  across  the  center  of  the  spindle, 
which  now  moves  endwise  toward  the  surface  of  the  egg.  A 
small  protrusion  is  made,  the  spindle  divides  across  the  center, 
and  the  first  polar  cell,  consisting  of  a  nucleus  with  chromo- 
somes and  a  small  amount  of  cytoplasm,  is  formed  and  thrown 
off.  The  remaining  portion  of  the  spindle  disappears.  The 
other  centrosome  divides  into  two  and  forms  another  spindle, 


SEGMENTATIOX  385 

on  which  the  chromosomes  are  again  arranged  as  before,  and 
the  second  polar  cell  is  formed.  These  polar  cells  disintegrate. 
The  nucleus  of  the  ovum  now  contains  only  about  half  the 
number  of  chromosomes  present  before  the  process  of  throwing 
off  the  polar  bodies.  This  remaining  portion  of  the  nucleus 
retires  from  the  circumference  and  is  called  the  female  pro- 
nucleus, or  macrogamete,  which  is  ready  for  fertilization.  The 
spermatozoon  previous  to  entering  the  ovum  undergoes  a 
similar  reduction  of  chromosomes,  though  the  resulting  cells 
form  sperms. 

Fertilization. — The  enveloping  membrane  of  the  ovum  con- 
tains one  or  more  minute  openings  through  which  the  sper- 
matozoon, or  male  germ  cell,  enters  for  the  purpose  of  fertiliza- 
tion. The  spermatozoon  consists  of  a  nucleus  or  extremely 
minute  head,  a  centrosome,  and  a  flagellum  or  tail,  which  is 
for  the  purpose  of  locomotion  and  disappears  upon  the  entrance 
of  the  spermatozoon  into  the  ovum.  The  nucleus,  called  the 
male  pronucleus  or  microgamete,  enlarges,  the  centrosome 
divides,  and  a  mitotic  figure  is  formed  which  moves  toward  the 
female  pronucleus,  which  moves  toward  the  male  pronucleus. 
Finally,  male  and  female  nuclei  meet  in  the  midst  of  the  spindle 
formed  about  the  male  nucleus;  thus  the  male  and  female 
nuclei  are  united  into  one  nucleus  or  zygote. 

Segmentation. — This  zygote  or  fertilized  ovum  now  contains 
the  normal  number  of  chromosomes  or  "hereditary  threads" 
for  its  species,  one-half  of  which  have  been  furnished  by  the 
maternal  cell  and  one-half  by  the  paternal  cell.  When  the 
process  of  mitosis  is  completed,  this  zygote  is  divided  into  two 
daughter-cells,  each  containing  the  same  number  of  chromo- 
somes, half  of  which  have  been  derived  from  the  sperm  and  half 
from  the  ovum.  Each  of  these  daughter-cells  subdivides  into 
two,  and  the  resulting  four,  into  eight  cells,  and  so  on,  the  num- 
ber varying  with  different  species.  When  there  is  little  or  no 
yolk  or  nutritive  material  the  whole  egg  divides  equally;  when 
there  is  much  yolk  the  division  is  unequal  or  partial. 

Dififerentiation  of  Tissues. — From  the  ectoderm  are  produced 
the  outer  portion  of  the  skin  and  its  outgrowths  and  the  whole 
nervous  system;  from  the  endoderm  come  the  lining  of  the  di- 
gestive tract  and  the  essential  parts  of  the  glands  connected  with 

25 


386  THEORIES    OF    DEVELOPMENT 

it.  The  mesoderm  gives  rise  to  the  bones  and  muscles,  the  cir- 
culatory system,  and  the  muscular  walls  of  the  alimentary  tube. 
All  metazoans  pass  through  these  early  stages  of  development, 
and  embryology  teaches  that  from  these  simple  beginnings  the 
most  complex  animal  body  is  developed. 

This  sphere  of  cells  is  known  as  the  morula  or  mulberry  stage 
(Fig.  5),  and  is  succeeded  by  the  l)lastula  stage,  in  which  the 
cells  are  arranged  in  a  circle  about  a  cavity  filled  with  watery 
fluid.  On  account  of  inequalities,  one  portion  of  this  sphere 
becomes  pitted,  this  pitting-in  grows  deeper  until  there  is  a 
complete  invagination  of  this  portion,  like  the  pushing  in  of  one 
side  of  a  hollow  rubber  ball  until  the  two  sides  touch.  This  is 
called  the  gastrula  stage,  and  occurs  in  all  the  main  divisions 
of  the  animal  kingdom.  (In  many  vertebrates  delamination 
supercedes  or  follows  invagination,  but  this,  perhaps,  "is  a 
later  development  or,  possibly,  improvement  upon  gastrula- 
tion.'")  This  gastrula  stage  is  an  open  sac  composed  of  two 
layers  of  cells,  the  outer  or  ectoderm,  and  the  inner  or  endoderm. 
In  most  cases  a  third  mass  of  cells,  the  mesoderm  or  middle 
layer  is  formed,  probably  from  the  endoderm.  The  opening 
of  this  sac-like  body  becomes  the  primitive  mouth. 

History  and  Theories  of  Evolution. — Evolution  is  not  a  new 
theory.  Traces  of  such  an  idea  are  found  in  old  Greek  phil- 
osophy. Empedocles  (about  500  b.  c.)  believed  that  "plants  first 
sprang  from  the  earth  while  the  latter  was  in  process  of  devel- 
opment. After  them  came  the  animals,  their  parts  having 
first  formed  themselves  independently  and  then  been  joined  by 
love."  After  ceaseless  trials,  nature  succeeded  in  producing 
fit  tribes  for  perpetuation.  Osborn  says  this  is  the  germ  of  the 
"survival  of  the  fittest."  Aristotle  (384-322  b.  c),  though 
believing  in  separate  creation,  taught  vaguely  that  living  baings 
formed  a  gradual  succession  from  the  "less  to  the  more  perfect." 
Aristotle  laid  great  stress  upon  the  inductive  method  of  study, 
and  he  was  so  great  an  observer  of  animals  as  well  as  a  collector 
of  the  statements  of  others  concerning  them  that  he  has  been 
called  the  founder  of  zoology.  If  only  his  principle — that  "we 
must  not  accept  a  general  principle  from  logic  only,  but  must 
prove  its  application  to  fact;  for  it  is  in  facts  that  we  must 
1  Romanes'  "Darwin  and  After  Darwin." 


HISTORY    AND    THEORIES    OF    EVOLUTION  387 

seek  general  principles,  and  these  must  always  accord  with 
facts" — had  been  remembered  and  applied  by  him  and  his 
successors,  science  need  not  have  progressed  so  slowly  for  so 
many  centuries. 

The  special  creation  theory  interrupted  scientific  thought 
and  investigation  for  many  centuries.  Philosophy  preceded 
science  in  the  line  of  evolutionary  thought.  Leibnitz,  a  German 
philosopher  (1646-1716),  believed  that  "living  beings  form  an 
unbroken  series  from  the  simple  to  the  complex,  some  steps  in 
the  series  having  become  extinct."^  Buffon  (1707-88)  thought 
that  organisms  could  be  modified  by  changes  in  food  and  envi- 
ronment or  by  domestication,  and  that  parts  could  be  modified 
by  disuse.  He  was  one  of  the  first  to  attempt  an  explanation 
of  the  geographic  distribution  of  animals. 

Erasmus  Darwin  (1781-1802),  grandfather  of  Charles 
Darwin,  author  of  "The  Origin  of  Species,"  was  a  physician  and 
physiologist  as  well  as  a  gardener  and  lover  of  plants.  He 
thought  that  the  various  plants  and  animals  were  descended 
from  "few  ancestral  forms  or  possibly  from  one  and  the  same 
kind  of  vital  filaments."  He  emphasized  function,  saying  that 
"from  their  first  rudiment  or  primordium  to  the  termination 
of  their  lives  all  animals  undergo  perpetual  transformations; 
which  are  in  part  produced  by  their  own  exertions  in  conse- 
quence of  their  desires  and  aversions,  of  their  pleasures  and  their 
pains,  or  of  irritations  or  of  associations;  and  many  of  these 
acquired  forms  or  propensities  are  transmitted  to  their  poster- 
ity." 

Lamarck  (1744-1829),  although  unappreciated  in  his  own 
day,  scientists  of  the  present  day,  whether  agreeing  with  him  or 
not,  admit  to  be  one  of  the  bravest  of  pioneers.  Haeckel 
says  "to  Lamarck  will  remain  the  immortal  glory  of  having  for 
the  first  time  established  the  theory  of  descent  as  an  independ- 
ent, scientific  generalization  of  the  first  order  as  the  foundation 
of  the  whole  of  biology."  To  quote  Lamarck,  "Nature  in  all 
her  work  proceeds  gradually  and  could  not  produce  all  animals 
at  once.  At  first  she  formed  only  the  simplest,  and  passed 
from  these  on  to  the  most  complex."  He  gives  four  laws  as 
the  summing  up  of  his  ideas: 

1  McFarland's  "  Biology." 


388  THEORIES  OF  DEVELOPMENT 

(1)  "Life  by  its  inherent  power  tends  continually  to  increase 
the  volume  of  every  living  body,  and  to  extend  the  dimensions 
of  its  parts  up  to  a  self-regulated  limit. 

(2)  "The  production  of  a  new  organ  in  an  animal  body  re- 
sults from  the  occurrence  of  some  new  need  which  continues  to 
make  itself  felt,  and  from  a  new  movement  which  this  need 
originates  and  sustains. 

(3)  "The  development  of  organs  and  their  power  of  action 
are  constantly  determined  by  the  use  of  these  organs. 

(4)  "All  that  has  been  acquired,  begun,  or  changed  in  the 
structure  of  individuals  during  the  course  of  their  life  is  pre- 
served in  reproduction  and  transmitted  to  the  new  individuals 
which  spring  from  those  which  have  experienced  the  changes." 

But  the  man  whose  work  is  most  completely  identified  with 
organic  evolution  is  Charles  Darwin  (1809-82),  who  after 
spending  many  years  in  travel,  observation,  and  investigation, 
published  in  1858  a  paper  of  great  scientific  interest.  At  the 
same  time,  by  the  arrangement  of  friends,  Wallace,  then  in  the 
Malay  Archipelago,  published  his  paper,  giving  essentially  the 
same  conclusions.  In  1859  Darwin  published  his  great  work, 
"The  Origin  of  Species,"  in  which  natural  selection  was  more 
fully  elaborated. 

All  organisms  vary.  These  variations  may  be  due  to  envi- 
ronmental changes  or  to  excess  of  food,  to  the  inherited  effect  of 
use  or  disuse  of  parts,  or  to  atavism,  reverting  to  the  character- 
istics of  a  remote  ancestor,  or  to  reversion,  a  character  or 
structure  found  in  more  recent  ancestors.  Darwin  emphasizes 
the  fluctuating  or  indefinite  variations  as  of  most  use  in  natural 
selection.  Every  plant  or  animal  must  struggle  for  existence 
because  of  the  vast  number  of  other  plants  and  animals  and 
because  of  conditions  of  environment,  such  as  cold,  heat,  or 
drouth.  This  struggle  is  threefold:  (1)  with  its  own  species; 
(2)  with  other  species  of  plants  or  animals  which  may  prey 
upon  it  or  its  food,  and  (3)  against  unfavorable  conditions  of 
climate  or  weather.  Those  which  most  frequently  survive  do 
so  because  of  certain  individual  characteristics  which  have  made 
them  able  to  win  in  this  struggle  for  existence,  or,  as  Spencer 
says,  "the  fittest  survive."  Now,  according  to  Darwin,  nature 
takes  advantage  of  these  favorable  variations  possessed  by  the 


HISTORY    AND    THIOORIES    OF    EVOLUTION  389 

survivors,  and  they  are  transmitted  by  heredity  to  their  off- 
spring, while  those  having  less  favorable  adaptations  do  not 
survive  and,  hence,  are  eliminated.  Thus  did  Darwin  think 
that  species  came  into  existence — by  a  gradual  improvement 
of  advantageous  variations  until  the  type  was  best  adapted 
to  its  surroundings.  "I  am  convinced,"  he  said,  "that  natural 
selection  has  been  the  main  though  not  the  exclusive  means  of 
modification." 

One  of  the  many  objections  offered  against  this  theory  is  the 
perpetuation  and  improvement  of  disadvantageous  modifica- 
tions, such  as  the  beautiful  colors  and  songs  of  l)irds  and  adap- 
tations for  fighting  which  render  them  conspicuous.  Darwin 
explained  many  of  these  cases  by  his  theory  of  sexual  selection. 
Among  the  higher  animals  it  is  a  fact  of  common  observance 
that  in  mating  the  members  of  either  sex  prefer  the  most  at- 
tractive individuals  of  the  opposite  sex.  The  successful  rival 
wins  the  mate,  and,  of  course,  it  is  his  characteristics  which  are 
transmitted  and  improved  in  succeeding  generations.  Adap- 
tations for  rivalry  by  battle  among  males  are  explained  in  the 
same  way. 

Among  the  helpful  contemporaries  of  Darwin  several  must  be 
mentioned.  To  Herbert  Spencer  (1820-1903),  the  philosopher 
and  author  of  "Principles  of  Biology,"  we  owe  the  phrase, 
"the  survival  of  the  fittest."  Haeckel  summed  up  the  recapit- 
ulation theory  of  Von  Baer  (published  in  1828) — i.  e.,  that  the 
embryonic  phases  of  higher  forms  resemble  or  pass  through  the 
corresponding  embryonic  stages  of  lower  forms — in  his  funda- 
mental law  of  biogenesis,  that  ontogeny  recapitulates  philogeny. 
Huxley  was  the  author  of  "Man's  Place  in  Nature." 

Dr.  August  Weismann  (born  in  1834)  is  the  foremost  oppo- 
nent of  Lamarck  as  to  transmission  of  acquired  characters.  He 
led  to  the  critical  examination  of  reported  cases,  and  he  claims 
that  no  case  really  shows  the  transmission  of  acquired  char- 
acters. He  recognizes  the  chromatin  as  the  hereditary  sub- 
stance or  idioplasm,  and  calls  the  idioplasm  of  the  germ  cells 
germ  plasm.  This  germ  plasm,  he  says,  is  "never  formed  de 
novo,  but  it  grows  and  increases  ceaselessly ;  it  is  handed  on  from 
one  generation  to  another  like  a  long  root  creeping  through  the 
earth,  from  which  at  regular  distances  shoots  grow  up  and  be- 


390  THEORIES    OF    DEVELOPMENT 

come  plants,  the  individuals  of  the  successive  generations." 
He  further  states  "that  only  those  characters  are  transmissible 
which  have  been  controlled — i.  e.,  produced — by  determinants  of 
the  germ,  and  that  consequently  only  those  variations  are 
hereditary  which  result  from  the  modification  of  several  or  many 
determinants  in  the  germ  plasm,  and  not  those  which  have 
arisen  subsequently  in  consequence  of  some  influence  exerted 
upon  the  cells  of  the  body.  In  other  words,  it  follows  from  this 
theory,  that  somatogenic  or  acquired  characters  cannot  be  trans- 
mitted. 

"This,  however,  does  not  imply  that  external  influences  are 
incapable  of  producing  hereditary  variations;  on  the  contrary, 
they  always  give  rise  to  such  variations  when  they  are  capable 
of  modifying  the  determinants  of  the  germ  plasm.  Climatic 
influences,  for  example,  may  well  produce  permanent  variations 
by  slowly  causing  gradually  increasing  variations  to  occur  in 
the  determinants  in  the  course  of  generations.  The  primary 
cause  of  variation  is  always  the  effect  of  external  influences. 
When  deviations  only  affect  the  soma  they  give  rise  to  temporary 
non-hereditary  variations;  but  when  they  occur  in  the  germ 
plasm  they  are  transmitted  to  the  next  generation  and  cause 
corresponding  hereditary  variations  in  the  body.'^ 

The  Mutation  Theory. — De  Vries  is  the  chief  exponent  of  the 
mutation  theory,  though  Bateson  also  emphasizes  its  import- 
ance. This  theory  assumes  that  new  species  and  varieties  are 
produced  from  existing  forms  by  sudden  leaps.  These  may 
arise  simultaneously  and  in  groups,  or  separately  and  at  more  or 
less  widely  distributed  periods.  This  new  theory  does  not 
try  to  account  for  these  sudden  variations,  but  claims  that 
"when  they  occur  it  is  a  striking  fact  that  the  characters  tend 
to  be  transmitted."  When  a  mutation  appears,  it  will  survive 
and  leave  descendants  if  it  is  adapted  to  its  environment.  Only 
a  comparatively  small  amount  of  evidence  has  been  found  to 
support  the  zoologic  side  of  proof  for  this  theory. 

Orthogenesis  is  believed  by  many  specialists,  among  whom 
may  be  mentioned  Eimer,  Whitman,  Tower,  and  Ruthven. 
Development  in  a  definite,  predetermined  direction,  even  if 
this  development  is  harmful  to  the  race,  is  called  orthogenesis. 
"According  to  this  theory,  certain  lines  of  development  remain 


HISTORY    AND    THEORIES    OF    EVOLUTION  391 

stationary  while  others  advance."  The  explanation  most 
favored  "ascribes  the  control  of  these  modifications  to  the  direct 
effects  of  physiochemical  factors  on  organisms."  Professor 
Whitman  says,  "Natural  selection,  orthogenesis,  and  mutation 
appear  to  present  fundamental  contradictions,  but  I  believe 
that  each  stands  for  truth,  and  reconciliation  is  not  distant." 

Mendel's  law  affirms  that  when  mating  takes  place  between 
two  animals  unlike  in  some  characteristic,  the  offspring  will 
often  exhibit  the  characteristic  of  only  one  parent.  This 
characteristic  is  said  to  be  dominant,  while  the  character  which 
does  not  appear  in  the  immediate  descendants  is  said  to  be 
recessive.  The  hybrids  which  result  from  the  crossing  of  ani- 
mals will  produce  a  number  of  germ  cells  which  bear  only  the 
pure  character  of  one  parent  and  the  same  number  which  bear 
only  the  pure  character  of  the  other  parent. 

From  this  law  follows  the  occurrence  in  the  next  and  succeed- 
ing hybrid  generations  of  a  definite  numl^er  of  forms  in  definite 
numerical  proportions.  Thus,  when  gray  rabbits  are  crossed 
with  albino  rabbits,  all  the  immediate  offspring  are  gray,  while 
in  the  next  generation  produced  by  the  breeding  together  of 
these  gray  hybrids  there  will  occur  in  nearly  every  case  three 
gray  young  to  one  albino.  This  is  explained  in  the  following 
way:  the  second  generation  is  all  gray  because  in  the  zygote,  or 
fertilized  germ  cell,  the  chromosomes,  or  hereditary  units,  which 
bear  the  gray  character  are  more  potent  in  the  color  of  the  young 
than  are  the  chromosomes  bearing  the  albino  character.  This 
gray  character  is  said  to  be  dominant ;  the  recessive  albino  char- 
acters are  not  destroyed,  but  are  carried  over  and  give  rise  to 
chromosomes  of  their  own  character,  so  that  in  the  breeding 
of  two  hybrids  one  albino  germ  cell  from  each  of  the  two  sexes 
unite  to  produce  one  albino  descendant.  If  one  of  the  hybrid 
dominants  (gray)  is  mated  with  a  recessive  animal,  half  of  the 
young  are  hybrid  dominants  and  half  recessive.  One  who  has 
found  out  by  experiment  which  are  dominant  and  which  are 
recessive  characters  may  produce  several  distinct  types  within 
a  species.  If  future  experiments  add  support  to  this  law,  it  will 
then  be  explained  how  races  suddenly  spring  into  existence  and 
become  established. 

By  collecting  evidence  and  arranging  it  in  the  form  of  pedi- 


392  THEORIES    OF    DEVELOPMENT 

grees,  it  has  been  possible  to  demonstrate  in  man  the  existence 
of  several  characters  which  show  Mendelian  inheritance. 
Though  most  of  the  evidence  has  relation  to  abnormal  or  dis- 
eased conditions,  investigations  are  now  being  made  concerning 
pedigrees  of  normal  characters.  One  of  the  most  easily  ob- 
served is  the  natural  color  of  the  eye.  "To  what  extent  eye 
color  may  be  valuable  as  a  criterion  of  race  it  is  at  present  im- 
possible to  say,  but  if  it  is  ever  to  become  so,  it  will  only  be 
after  a  searching  Mendelian  analysis  has  disclosed  the  factors 
upon  which  the  numerous  varieties  depend. 

''A  discussion  of  eye  color  suggests  reflections  of  another 
kind.  It  is  difficult  to  l)elieve  that  the  markedly  different  states 
of  pigmentation  which  occur  in  the  same  species  are  not  as- 
sociated with  deep-seated  chemical  differences  influencing  the 
character  and  bent  of  the  individual.  May  not  these  differences 
in  pigmentation  be  coupled  with  and  so  become  in  some  measure 
a  guide  to  mental  and  temperamental  characteristics?"^ 
1  Punnett's  "  Mendelism." 


Equus  Beds. 

Equus,     Tapirug,  EUpkas. 
Pliohippus  Beds. 

PUMppug,  Maxtudan,  Bos, 


Miohippus  Beds. 

MiohxppUB,  IHceratherivm,  TJ 
Oreodon  Beds. 

Edentates,  Hyaenodon,  Hyracod' 
Brontotheiiuin  Beds. 

Mesohippus,  Menodttg,  Elotker 


Diplacodon   Beds. 

EpihippuB,  Amynodon. 
Dinoceras  Beds. 

Tinoceras,   Vintatlierium,  Lii 

Orohippus,  Betaletes,    Culoiw 
Coryphodon  Beds. 

Eohipput,     Monkeys,    Carnivc 
Serpents. 


I,    Ungulates.   Tillo'ionte,  Rodenti 


Lignite  Ser 


->igni 
Syd, 


Drypt09aurU9. 


?ianodoii  Beds, 
;irdfl  with  Teeth.   Hesperor 
Pterodactjls,  PlesiosaurB. 


Connecticut  River  Beds. 
First  Mammals    (Marsupials),    (/>i 
Dinosaur  Foot-prints,  Amphisaur 
Crocodiles  (BeUdon), 


Corniferous. 


Upper  Silurian. 
Lower  Silurian. 


Laurentian. 


Fig.  302. -Section  of  the  earth's  crust,  to  illustrate  vertebrate  life  in  America. 

(After  Marsh.)  (From  Le  Conte's  Geology,  American  Book  Co.,  Publishers.) 

393 


QUESTIONS,   PROBLEMS,   AND    SUGGESTIONS 
For  Study,  Review,  or  Examination 

An  animal  is  a  living,  organized  being  with  living  protoplasm  as  the 
essential  foundation  or  "The  Physical  Basis  of  Life."  An  animal,  whether 
an  ameha  or  a  bird,  is  more  marvelous  than  any  machine  man  ever  invented. 
The  animal  has  the  powers  of  nutrition  {i.  e.  is  auto-  or  self-feeding),  excre- 
tion (self-waste  eliminating),  self-metabolism  (power  to  change  substances 
into  others  of  different  chemical  composition),  irritability  (response  to 
stimuli),  contractility  (ability  to  move  itself),  sensitivity  and  special  senses 
(by  means  of  which  it  discovers  itself  and  its  environment),  and  self-repro- 
duction.    It  has  self-defense  and  automatic  (self)  response  or  rmvement. 

The  more  you  study  and  observe  animals,  the  more  marvelous  and  inter- 
esting they  become  until  you  enter  into  the  spirit  of  nature  study.  Then 
you  have  a  lifetime  of  enjoyment,  pleasure,  and  profit  ahead  of  you.  En- 
rich your  life.  Get  this  spirit  and  sympathy  with  animal  life,  as  John  Bur- 
roughs and  many  other  naturalists  have  done,  and  thus  greatly  enlarge 
your  life's  horizon. 

PROTOZOA 

1.  The  body  of  protozoans  consists  of  one  cell,  as  in  Ameba,  or  a  colony 
of  cells,  as  in  Gonium.  How  can  one  cell  do  all  that  is  essential  to  an 
animal's  existence — -in  nutrition,  growth,  reproduction,  locomotion,  de- 
fense, and  sensitivity  or  irritabilitj^? 

2.  The  symmetry  of  the  animal  body  is:  (1)  asymmetric,  as  in  the  Ameba; 
(2)  radial,  as  in  the  starfish;  or  (3)  bilateral,  as  in  most  of  the  animal  king- 
dom. How  does  the  symmetry  of  the  body  affect  its  locomotion?  What 
kind  of  motion  has  an  asymmetric  animal,  e.  g.,  the  Ameba?  One  of 
radial  symmetry,  as  the  starfish?     One  of  bilateral  symmetry,  as  the  bird? 

3.  What  are  the  means  and  manner  of  locomotion,  nutrition,  reproduc- 
tion, behavior,  and  defense  of  Protozoa? 

4.  The  struggle  for  existence  is  threefold:  (1)  with  their  own  kind;  (2) 
with  different  kinds;  (3)  with  their  fivefold  environment.  Which  do  you 
consider  the  most  severe,  and  why? 

.5.   Environment  is  fivefold:     (1)  organic  or  life;  (2)  atmospheric;   (3) 
u(!ue(;us  (water  in  its  various  forms);  (4)  igneous  or  heat;  and  (5)  terranean 
(the  solid  earth) .     Which  one  of  this  fivefold  invironment  affects  protozoans 
most  in  their  struggle  for  existence? 
394 


PORIFERA  395 

6.  Heredity. — How  would  you  define  heredity,  and  what  evidence  do 
you  see  of  it  in  the  Protozoa  f 

7.  Which  do  you  consider  the  more  important  factor  in  the  hves  of  ani- 
mals, heredity  or  environment?  Which  factor  or  force  do  you  consider 
the  stronger  one  in  their  existence?     Why? 

8.  Mind  (p.  8). — Do  you  see  any  evidence  of  mind  in  Protozoa? 

9.  Multiplication. — Give  examples,  from  the  text,  of  multiplication, 
asexual  and  by  conjugation  in  Protozoa. 

10.  Colonial  Protozoa. — Gonium,  for  example,  has  "a  group  of  sixteen 
cells,  each  cell  a  complete  perfect  animal  capable  of  living  independently, 
but  all  holding  together  to  form  a  tiny,  flat  colony"  (Jordan).  What 
is  the  difference  between  a  colony  and  an  individual,  for  example, 
a  bee? 

11.  Whether  the  animal  body  is  one  celled,  as  in  Atneha,  a  colony  of  cells, 
as  in  Gonium,  or  many  celled,  as  in  the  higher  forms,  does  not  the  living 
protoplasm  of  Protozoa  foreshadow  the  animal  world,  with  all  its  com- 
plexity of  body  and  animal  behavior?     (Mind,  p.  8.) 

12.  Show  clearly  that  the  Ameha  is  the  hmit  of  simphcity  for  an  animal  in 
body  and  behavior  (Mind,  p.  8),  but  that  it  has  all  the  essential  .elements, 
or  is  potentially  all  that  any  of  the  higher  forms  are  as  to  animal  body  and 
animal  behavior. 

PORIFERA 

1.  Body,  many  celled.  The  plan  of  arrangement  of  these  many  cells 
is  in  layers  around  a  hollow  center.  Hence,  sponges  and  the  following 
branch,  Coelenterata,  are  sometimes  called  "hollow  animals."     See  Fig.  4. 

2.  Symmetry  of  .sponge  body?  Body  layers?  (p.  10).  Body  differen- 
tiation? (p.  10). 

3.  Discuss  increasing  complexity  of  body  structure  of  sponges  over  that 
of  the  protozoan  body. 

4.  Compare  the  threefold  .struggle  for  existence  and  the  fivefold  en- 
vironment of  Porifera  and  Protozoa.  Which  branch  shows  the  better 
preparedness  for  existence?     Wh}'? 

5.  Behavior  of  Sponges  (p.  8,  Mind). — Do  you  discover  any  increasing 
complexity  (advance)  in  mind  in  sponges  over  mind  in  protozoans?  Would 
increasing  body  complexity  necessitate  more  mind  manifestations? 

C.  Discuss  variation  in  shape,  size,  color,  structure,  and  use  of 
sponges. 

7.  Economic  use  of  sponges  to  other  animals  and  to  man.  See  "Har- 
vesting Sponges,"  pp.  14,  1.5. 

8.  Skeleton. — Comment  on  structure  and  advance  over  that  of  proto- 
zoans. 

9.  Name  some  enemies  of  sponges.     Why  enemies? 


396  QUESTIONS,    PROBLEMS,    AND    SUGGESTIONS 

10.  Dominance. — Are  sponges  a  dominant  branch  of  animals?  Where 
most  abundant?  (p.  15).     Where  least  abundant?     Why? 

11.  Dispersal. — Name  means  and  manner  of  dispersal. 

12.  Barriers. — Name  principal  environmental  barriers  and  state  why 
barriers. 

CCELENTERATA 

1.  Body  Plan. — A  two- layered,  sac-like  body  with  hollow  tentacles, 
e.  g.,  the  hydra  (p.  18). 

2.  Symmetry. — See  2  under  Protozoa. 

Significance  of  this  symmetry  to  the  locomotion  of  the  co^lenterates? 

3.  What  are  the  means  and  manner  of  nutrition,  reproduction,  locomo- 
tion, behavior,  defense,  and  dispersal? 

4.  Name  the  most  important  of  the  eight  factors  or  forces  in  the  three- 
fold struggle  for  existence  and  the  fivefold  environment  of  this  branch. 

5.  What  are  the  variations  in  the  body  plan  (appendages  included), 
body  nutrition,  reproduction,  dispersal,  barriers,  food,  and  economic  use 
or  value  of  the  four  classes  of  this  branch? 

6.  Note  increasing  complexity  of  the  animals  of  this  branch  over 
sponges  in  body  plan. 

7.  Behavior  or  Mind  (p.  8). — Manifestations  of?  Advance  over 
sponges? 

8.  Alternation  of  Generations. — Give  a  brief  account  of  it  in  the  classes 
of  this  branch. 

9.  Specialization,  differentiation,  or  division  of  labor  in  this  branch. 
Comment  on,  as  seen  in  Figs.  15,  16,  18,  21. 

10.  What  do  the  following  terms  mean,  as  used  in  tliis  branch:  colony; 
medusa,  zooids? 

11.  Compare  the  hydra  (Fig.  10)  and  Physalia  (Fig.  16);  hydra  and 
coral-polyp;  hydra  and  sponge;  and  hydra  and  ameba,  as  to  body  plan, 
nutrition,  multipUcation,  defense,  and  animal  behavior.  (See  Lab.  Guide, 
pp.  12-14.) 

12.  Primitive  or  Generalized  Form. — From  what  generalized  or  primitive 
form  do  you  consider  that  the  four  present  classes  of  this  branch  originated? 

13.  Phosphorescent  Forms. — What  classes  of  this  branch  furnish  phos- 
phorescent animals?     What  is  the  function  of  the  phosphorescence? 

14.  Economic  value  to  man  (p.  32). 

15.  What  are  the  special  body  structures  that  interest  you  in  the  forms 
illustrated  in  Figs.  10  to  21? 

16.  Increasing  Complexity. — In  what  body  structures  or  behavior 
(mind)  manifestations  have  the  ccelenterates  increased  in  complexity 
over  the  sponges? 

17.  How  would  you  summarize  the  coelenterates? 


WORMS  SO"} 


WORMS 


1.  Shape  of  body — flat,  round,  or  rigid. 

2.  Symmetry. — (See  p.  34.) 

3.  Body  Slruclure. — (a)  Skeleton,  p.  34. 

(6)  Ccelom,  or  body  cavity,  pp.  34,  41,  65. 
(c)  Segmentation,  pp.  41,  65. 

4.  Body. — Form,  color,  covering,  and  locomotion  in  the  different 
branches  of  worms. 

5.  Compare  the  flat  worms  and  the  round  worms  as  to:  form,  body 
structure^  feeding  habits,  habitats,  use  and  harm  to  other  animals  and  to 
man. 

6.  Annidatn. — Compare  this  branch  (p.  65)  with  the  Flat  Worms  (p. 
34)  and  the  Round  Worms  (p.  41),  as  in  5. 

7.  Variation. — What  variations  do  you  discover  in  shape,  size,  color, 
covering,  feeding  habits,  habitats,  and  dispersal  in  the  three  branches  of 
worms  compared? 

8.  Economics. — Make  a  list  of  worms  considered  from  pp.  34-50,  and 
from  pp.  65-71,  and  state  their  interest  to  man  and  other  animals. 

9.  Animal  Behavior. — Do  you  discover  any  advance  in  animal  mind 
(p.  8)  in  worms  over  other  animals  so  far  studied?  See  Laboratory  Guide, 
pp.  12-16,  for  Animal  Behavior. 

10.  Do  you  discover  any  increasing  complexity  in  body  structure  and 
mind  manifestations  in  worms  over  other  forms  so  far  studied?     If  so,  what? 

11.  Read  and  report  on  Darwin's  Earthworm. 

12.  In  the  threefold  struggle  for  existence  and  the  fivefold  environment, 
which  of  the  eight  factors  is  most  apparent  in  the  existence  of  worms? 

13.  "Worms  are  distinguished  by  shape.  For  amid  the  diversity  we 
discover  affinities  with  coelenterates,  echinoderms,  arthropods,  molluscs, 
and  vertebrates"  (Thompson). 

What  affinities  can  you  discover  between  worms  and  the  forms  Thomp- 
son names?     Consider  also  the  larval  stages. 

14.  Discuss  manner  and  means  of  nutrition,  multiplication,  locomotion, 
defense,  and  behavior  of  worms. 

15.  What  is  a  worm?  Why  is  a  worm  a  worm?  Is  it  because  of  heredity, 
environment,  or  both?  Can  it  or  will  it  be,  was  it  ever  anything  else  than 
a  worm? 

16.  Structure  and  Function  of  (he  Worm-body: 

(1)  The  Dermal  System.  Describe  the  skin,  its  structure,  glands,  and 
covering,  if  any. 

(2)  The  Muscular  System.     Note  contractility  and  locomotion. 

(3)  The  Skeleton — the  supporting  apparatus  or  framework  of  the  body. 
Do  worms  have  a  skeleton?     If  so,  what  is  it? 


398.  QUESTIONS,    PROBLEMS,    AND    SUGGESTIONS 

,4)  The  Nervous  System  and  Special  Senses — the  co-ordinating  appa- 
ratus for  the  body  systems  and  the  mind,  or  animal  behavior. 

.  f  (5)  The  Digestive  System — the  means  of  absorption  from  food. 
.2  (6)  The  Circulatory  System — the  means  of  blood  nutrition  of  tissues. 
•"H  ]  (7)  The  Respiratory  System — the  means  of  oxygen  nutrition  of  tissues. 
^  (8)  The  Excretory  System — the  means  of  waste  elimination  of  body. 
[  (9)  The  Reproductive  System — the  race  repair  system.  Note  the 
function  of  each  of  the  nine  body  systems  enumerated  in  worms  or  other 
of  the  higher  forms. 

17.  Is  the  worm-body  a  typical,  characteristic  animal  body?  If  not, 
what  animal  would  you  designate  as  a  typical,  characteristic,  complete, 
perfect  animal  body? 

18.  Are  insect-bodies,  fish-bodies,  bird-bodies,  mammal-bodies  an  im- 
provement over  the  worm-body  model?     If  so,  in  what  respects? 

19.  Degeneration. — How  does  an  animal  body  begin  to  degenerate? 
What  organ  or  system  first  weakens  and  how  does  this  affect  other  organs 
or  systems?  How  does  degeneration  of  the  body  affect  the  mind  or  be- 
havior?    Give  examples  of  degenerate  worms. 

20.  Increasing  Complexity. — How  does  an  animal  body  advance  and  be- 
come more  complex?  How  does  the  animal  mind  or  animal  behavior  in- 
crease in  complexity?     How  degenerate?     Why? 

ECHINODERMATA 

1.  Bodij  Plan. — Symmetry  of  the  larval  body?  Of  the  adult  body? 
Metamorphosis  of  the  body?  (p.  56). 

2.  Living  forms  of  this  branch  solitary  or  gregarious?  Fixed  or  free? 
Marine  or  freshwater  habitat? 

3.  Skeleton  and  Covering. — Of  what  do  they  consist? 

4.  Name  means  and  manner  of  nutrition,  reproduction,  locomotion, 
dispersal,  and  defense. 

5.  Water-vascidar  System. — Its  structure  and  function?  Is  it  found  in 
any  other  branch?  (p.  54).     Why  this  specialization  for  this  branch? 

6.  Nervous  System  and  Special  Senses. — Of  what  do  they  consist  in  this 
branch? 

7.  Animal  Behavior  in  this  branch  as  compared  with  that  of  other 
branches  just  studied?     Any  advance  or  degeneration? 

8.  The  echinoderms  are  a  singularly  isolated  group  (p.  64).  How  would 
you  account  for  this?  What  is  the  effect  of  isolation  on  a  group  of  animals 
or  on  a  single  species?     What  is  the  peculiarity  of  the  hermit?     Why  so? 

9.  Economics. — Name  echinoderms  of  commercial,  or  scientific  use  or 
harm  to  man  (p.  55). 

10.   Hypothetic  Case. — If  you  could  do  so,  what  changes  would  you  make 


MOLLUSCA  399 

in  the  body  structure  of  a  starfish  to  change  it  to  a  sea-urchin?     A  sea- 
urchin  to  a  sea-cucumber?     A  sea-cucumber  to  a  crinoid  or  sea-Hly? 

1 1 .  Sequence  of  development  and  appearance  of  the  classes  of  echinoderms? 
■See  Geologic  Distribution,  Text,  pp.  56,  60,  62,  64,  and  Fig.  302. 

12.  Special  characteristics  of  this  branch.  Of  what  interest  are  the 
echinoderms  to  you? 

MOLLUSCA 

1.  Body  of  Mollusca. — Segmented  or  unsegmented?  Bilaterally  sym- 
metric or  asymmetric?     Covering?     Defense? 

2.  Variation  in  body  plan  and  covering  of  the  three  classes  of  Mollusca? 
o.  Economic  or  commercial  interest  or  value  to  man? 

4.  Oysters  or  Pearls. — Which  is  of  more  commercial  value  to  man? 

5.  Name  some  molluscs  that  are  solitary.     Gregarious,     ^^'hy? 

6.  Name  Mollusca  found  in  your  vicinity?     Use?     Harm? 

7.  Locomotion. — What  are  the  means  and  manner  of  locomotion  in  the 
three  classes  of  Mollusca?  Rate?  Name  sluggish  ones;  active  ones. 
Why  is  the  locomotion  so  slow?  Compensation  for  this  slowness?  Ex- 
ception:  see  Cuttlefishes,  p.  84. 

8.  Pearls. — Discuss  the  theory  of  their  origin.  Purpose  to  the  mollusc? 
To  man? 

9.  Shells. — How  do  you  account  for  Mollusca  developing  such  great 
defensive  armor?     Advantages?     Disadvantages  to  the  branch? 

10.  Affinities  of  molluscs  and  worms.     See  p.  SS  for  a  hint. 

11.  "The  molluscs  are  the  most  highly  organized  of  any  of  the  inver- 
tebrates except  the  Arthropoda."  Text,  p.  87.  Show  the  truth  or  falsity 
of  this  statement,  according  to  your  own  way  of  thinking. 

12.  "Chambered  Nautilus." — Read  it  and  show  how  and  why  O.  W. 
Holmes  has  "immortalized"  it. 

13.  Structure  and  function  of  the  molluscan  body.  See  16  under  Worms, 
and  compare  the  two  groups,  system  witii  system. 

14.  Compare  the  7nind  apparatus  (nervous  system  and  special  senses) 
and  the  mind  manifestations  of  molluscs  and  worms.  See  Laboratory 
Guide,  pp.  12-16,  Animal  Behavior. 

15.  Mind  Type.— Sluggish  or  alert?     (Cuttlefishes,  p.  84.) 

16.  Body  Type. — Sluggish  or  alert?     (Squid,  p.  So.) 

17.  Does  the  body-type  make  the  mind-type,  or  vice  versa? 

18.  Name  the  one  great  specialization  of  the  mollusc  as  to:  (1)  its  bodj^; 
(2)  its  mind  manifestations. 

19.  Dominance  as  a  branch  of  the  animal  world.  Is  it  persistent  geo- 
logically? 

20.  Summary  of  the  molluscan  branch  and  its  classes,  past  and  present 
(geologically). 


400  QUESTIONS,    PROBLEMS,    AND    SUGGESTIONS 


ARTHROPODA 

1.  Symmetry  of  body?     Segmentation  of  body  and  appendages? 

2.  Appendages. — State  number,  arrangement,  and  use  in  each  class 
of  Arthropoda. 

3.  What  are  the  means  and  manner  of  locomotion,  defense,  and  dis- 
persal in  each  class? 

4.  Nutrition. — (Digestive,  circulatory,  respiratory,  and  excretory  sys- 
tems and  the  organs  of  these  systems.) 

5.  Economics. — Name  ten  arthropods  of  interest  or  value  (scientific, 
commercial,  or  economic). 

6.  Compare  the  two  sub-classes  of  Crustacea  as  to:  (a)  plan  of  body 
structure;  (h)  appendages;  (c)  habitat;  (d)  locomotion;  and  (e)  value  to 
man  or  to  other  animals. 

7.  Compare  the  orders  of  class  Arachnida  in  structure,  habits,  habitat, 
use  and  harm  to  man  and  other  animals. 

8.  Compare  orders  of  Myriapodn  on  the  same  points.  Ditto  for  the 
orders  of  Insecta. 

9.  Enemies. — Make  a  list  of  enemies,  animate  and  inanimate,  that 
injure  or  destroj^  crustaceans,  arachnids,  myriapods,  and  insects  (in  the 
adult,  larval,  or  egg  stage). 

10.  Name  an  arthropod  that  shows  protective  resemblance;  warning 
colors  or  sounds;  alluring  colors  or  odors;  parasitism;  degeneration;  mim- 
icry; commensalism  or  symbiosis. 

11.  Eyes. — Name  an  arthropod  with  simple  eyes;  with  compound  eyes; 
with  both  simple  and  compound  eyes;  and  one  with  no  eyes. 

12.  Compare  the  four  clases  of  Arthropoda  as  to:  (1)  the  head  and  its 
appendages;  (2)  the  body  and  its  appendages;  and  (3)  the  abdomen  and 
its  appendages. 

13.  The  Young. — How  are  the  eggs  and  the  young  of  Arthropoda  pro- 
tected in  the  difTerent  classes? 

14.  Wings. — Name  arthropods  with  no  wings;  with  one  pair;  with  two 
pairs.     Why  this  difference? 

15.  Stages  of  Metamorphosis. — What  are  the  lari^ce  of  insects  called  in  the 
different  orders  of  insects?  W^hat  insects  furnish  the  pupa,  cocoon,  chrys- 
alis?    What  is  the  imago  of  insects  called  in  the  different  orders? 

16.  Name  an  order  of  insects  that  has  no  metamorphosis.  Why?  (see 
p.  12). 

17.  Degeneration. — What  orders  of  insects  show  examples  of  degeneration, 
and  why?     Of  luminosity  or  phosphorescence?  (p.  153). 

18.  Odors. — What  orders  give  examples  of  defensive  odors?  Of  alluring 
odors? 

19.  Glands. — Silk,  wax,  and  others.     Use  of  these  glands? 


THE    ELEVEN    BRANCHES    OF    THE    INVERTEBRATES        401 

20.  Colors. — Give  examples  of  alluring,  warning,  and  terrifying  colors; 
also  of  protective  resemblance. 

21.  Tools,  weapons,  or  other  means  of  offense  or  defense? 

22.  Does  Campodea  show  worm-Uke  ancestry?  If  so,  what  is  the  line  of 
descent  of  insects? 

23.  From  Campodea,  or  some  other  primitive  form,  how  would  you 
account  for  the  orders  of  insects  by  descent  with  modification? 

24.  Wheeler  (in  "Ants")  attributes  the  dominance  of  ants  to  their  (1) 
universal  variabiUty;  (2)  wide  distribution;  (3)  numerical  ascendancy;  (4) 
longevity;  (5)  abandonment  of  detrimental  specialization;  and  (6)  versa- 
tility of  their  relations  with  plants  and  other  animals. 

Compare  other  animals  on  these  six  points  as  to  their  dominance.  What 
are  your  conclusions? 

25.  Dominance. — Is  success  the  criterion  of  superiority  in  animals  and 
plants?  If  so,  what  are  the  superior  classes  of  Arthropodaf  The  dominant 
or  superior  order  of  Crustacea?  of  Arachnida?  of  Myriapodaf  Of  insects, 
the  dominant  species  of  Arthropodaf 

26.  Preparedness. — What  arthropods  are  best  prepared  (and  in  what 
ways  do  you  mean?)  to  maintain  the  struggle  for  existence?  - 

27.  Compare  the  complexity  of  body  structure  and  mind  manifestations 
of  Arthropoda  with  that  of  worms  in  general.  See  16  under  Worms  for 
body  systems  and  animal  behavior.     Laboratory  Guide,  pp.  12-14. 

THE   ELEVEN   BRANCHES   OF  THE     INVERTEBRATES 

1.  W^hat  have  they  in  common  in  structure  that  makes  them  rank  as 
invertebrates? 

2.  How  does  the  branch  Chordata  differ  in  structure  from  the  inver- 
tebrates?    See  Chordata,  p.  189. 

3.  Give  three  general  characteristics  of  each  branch  of  the  invertebrates, 
as  to  their  body-  and  appendage-segmentation,  body  symmetry,  body- 
structure  as  to  body  or  germ  layers  (ectoderm,  mesoderm,  and  endoderm). 

4.  Symmetry. — What  branches  afford  examples  of  radial  symmetry? 
of  bilateral  symmetry?  of  asymmetric  symmetry?  of  more  than  one  kind 
of  symmetry?     Influence  of  symmetry  on  the  locomotion  of  animals? 

5.  Habitat. — What  branches  show  aquatic  forms?  aerial  forms?  ar- 
boreal? terrestrial?  subterranean?  What  branches  show  more  than  one 
habitat?     Any  exclusively  marine  forms?  fresh-water  forms? 

6.  Food. — What  branches  have  carnivorous  forms?  herbivorous  ones? 
omnivorous  ones? 

7.  Locomotion. — Name  and  trace  all  means  and  modes  of  invertebrate 
locomotion.  Do  any  branches  have  a  common  kind  of  locomotion?  If  .so, 
what  ones? 

26 


402  QUESTIONS,    PROBLEMS,    AND    SUGGESTIONS 

8.  Self-defense. — Name  and  trace  all  the  means  and  modes  of  defense  of 
the  eggs,  the  young,  or  of  the  adult  invertebrate. 

9.  Rivalry. — Trace  all  adaptations  for  rivalry  by  (1)  battle,  (2)  song; 

(3)  color,  or  other  means. 

10.  Covering. — Name  and  trace  through  the  different  invertebrate 
branches  all  means  of  covering  the  body;  state  wjiat  it  is  called  and  its  uses 
to  the  animal  and  to  man. 

11.  Color. — Trace  the  purpose  of  color  or  color  patterns.  P'ind  examples 
of  warning  colors,  alluring  colors,  terrifying  colors,  of  colors  for  protective 
resemblance.     What  gives  color  to  an  animal? 

12.  Parasites. — Trace  parasitism  through  the  invertebrates.  Causes? 
Results  of  parasitism  on  the  parasite  and  upon  the  host? 

13.  In  the  threefold  struggle  for  existence,  which  fold  is  the  most  ap- 
parent for  the  invertebrates?     Why? 

14.  Of  the  five  great  environmental  factors,  which  one  is  the  most  ap- 
parent in  the  existence  of  the  invertebrates? 

15.  Heredity. — In  what  ways  do  you  see  or  infer  that  heredity  holds  the 
invertebrates?     i.  e.,  Why  do  they  remain  invertebrates? 

16.  Recognition. — Find  examples  of  recognition  of  its  own  or  different 
species  by  color,  sound,  odor,  or  shape. 

17.  Terrifying  appearance,  attitude,  or  sound.  Find  invertebrate  ex- 
amples of  each. 

18.  Relations  with  Other  Animals. — Find  examples  of:  (1)  solitary  inver- 
tebrates; (2)  gregarious  ones;  (3)  social  ones;  (4)  commensalism;  (5)  sym- 
biosis. 

19.  Multiplication. — Find  examples  of:  (1)  asexual  invertebrates;  (2) 
hermaphroditic  ones;  (3)  dimorphic,  trimorphic,  and  polymorphic  ones; 

(4)  parthenogenetic  ones;  (5)  of  branches  that  afford  examples  of  both 
asexual  and  sexual  ones. 

20.  Show  that  its  object  is  variation  rather  than  reproduction,  as  there 
was  reproduction  long  before  sex  existed. 

21.  Dispersal. — Name  direct,  as  well  as  indirect,  means  of  invertebrate 
dispersal. 

22.  Barriers. — Show  that  large  rivers,  oceans,  etc.,  are  barriers  to  in- 
vertebrates. 

.23.  Animal  Behavior. — See  "Animal  Behavior,"  Laboratory  Guide,  i)p. 
12-16. 

24.  Irritability. — Trace  irritability  of  the  protoplasm  from  Ameba. 
Will  it  develop  into  the  nervous  system  and  special  senses  of  the  higher 
invertebrates?  If  not,  where  do  the  nervous  system  and  special  senses 
originate? 

25.  Contractility. — Will  protoplasmic  contractility  develop  into  the  mus- 
cular system,  and  locomotion? 


PISCES  403 

26.  Trace,  touch,  taste,  smell,  sight,  and  hearing  through  the  inver- 
tebrate branches. 

27.  Trace  evidences  of  automatic  and  reflex  action.  Purpose  of  these 
actions  to  animals? 

28.  Egoistic  Instincts. — (Instincts  for  the  good  of  the  individual.)  See 
Laboratory  Guide,  p.  14,  for  a  list  of  these  instincts  and  give  invertebrate 
examples  of  each  one. 

29.  Altruistic  Instincts. — (Instincts  for  the  good  of  the  race.)  See  La- 
boratory Guide,  p.  14,  for  list  and  find  examples  of  each  one  among  the  in- 
vertebrates. 

30.  Emotions. — Laboratory  Guide,  p.  16.  Plnd  invertebrate  examples  of 
each.     Purpose  of  emotions  in  the  existence  of  invertebrates? 

31.  Trace  invertebrate  sounds,  memory,  intelligence,  and  reason,  if  any. 
State  the  purpose  of  each  to  animals;  to  man. 

32.  Compare  the  invertebrate  body-structvire  with  that  of  the  chordate 
(vertebrate),  as  to  similarities  and  differences. 

33.  Have  they  both  the  nine  systems  named  in  16,  under  Worms? 

34.  Mind  manifestations  of  the  invertebrates  and  vertebrates.  Do  they 
agree,  or  do  they  differ  in  degree  and  kind? 

35.  Is  the  invertebrate  body-structure  superior  or  inferior  to  the  chordate 
one?  The  mind  manifestations?  Is  the  invertebrate  body-mind  superior 
or  inferior  to  the  chordate  body-mind? 

36.  Will  either  body-mind  tyj)e  ever  advance  to  a  higher  type  of  body- 
mind?  Will  there  ever  be  a  higher  type  of  body-mind  or  of  mind-body? 
Why  do  you  think  so?  Will  either  type  now  existing  ever  degenerate? 
Become  extinct? 

PISCES 

1.  Fins. — How  do  you  account  for  the  anterior  and  posterior  paired 
fins  of  fishes  being  placed  so  close  together  as  compared  with  the  paired 
limbs  in  other  chordates?  Does  the  body  locomotion  of  fishes  have  any- 
thing to  do  with  this  arrangement? 

2.  Gills. — How  do  you  account  for  the  presence  of  gills  instead  of  lungs 
in  fishes?     Advantages?     Disadvantages? 

3.  Fins  and  Scales. — Why  have  fins  and  scales?  Is  locomotion  con- 
cerned in  this? 

4.  Self-defense. — Name  all  the  ways  and  means  of  self-defense  used  and 
possessed  by  fishes. 

5.  Locomotion. — Body  motion,  limb  motion,  or  both?  Name  all  the 
modes  of  motion  and  locomotion  of  fishes. 

6.  Enemies. — Name  all  enemies  of  fishes,  both  animate  and  inanimate. 
How  do  fishes  combat  or  escape  their  enemies? 


404  (iUESTIONS,    PROBLEMS,    AND    SUGGESTIONS 

7.  Sotmds  or  Noises. — Name  some  fishes  that  make  a  sound  or  noise. 
Why  are  fishes,  as  a  class,  silent? 

8.  Intelligence  of  Fishes. — High,  medium,  or  low  as  compared  with  in- 
vertebrates?    As  compared  with  other  classes  of  chordates? 

9.  Dominance. — Why  are  fishes  a  dominant  aquatic  class?  Why  more 
so  than  the  amphibians  or  the  reptiles?  Why  are  fishes  the  most  dominant 
aquatic  chordate  class? 

10.  Geologic  Histonj.— What  was  the  status  of  the  fish  class  in  past 
geologic  time  as  an  aquatic  class?  Was  it  dominant  as  compared  with  the 
reptilian  class?  See  your  Geology  and  compare  the  past  of  fishes  and  rep- 
tiles. 

11.  Consult  "American  Food  and  Game  Fishes."  Of  the  1000  true  food 
and  game  fishes  discussed,  report  things  of  interest,  value,  and  variation 
in  the  ten  leading  families  of  fishes. 

AMPHIBIA 

1.  How  do  you  account  for  the  amphibious  Hfe  (i.  e.,  living  both  in  the 
water  and  on  land)?     Advantage  to  the  class?     Disadvantage  to  the  class? 

2.  "No  amphibians  are  marine."  How  do  you  account  for  this?  Is 
it  an  advantage  or  a  disadvantage  to  the  class? 

3.  How  do  you  account  for  the  other  classes  of  chordates  having  marine 
forms? 

4.  Limbs. — Name  amphibians:  (1)  with  four  limbs;  (2)  some  with  two; 
and  (3)  others  with  none.     Why  this  difference? 

5.  Respiradon. — In  the  tadpole  stage?  In  the  adult  stage?  Why 
this  difference? 

6.  Defense. — In  the  larval  stage?     In  the  adult  stage? 

7.  Enemies — of  all  kinds  for  the  young?     For  the  adult? 

8.  Care  of  Young. — Various  ways?     Name  of  the  young? 

9.  Locomotion. — How  performed  in  the  larval  and  in  the  adult  stage? 

10.  Sounds  or  Noises. — How  made?  Why  made?  Name  of  the  sound 
or  noise? 

11.  Variations  in  forms,  size,  and  shape  of  the  amphibian  body? 

12.  Hibernation,  Estivation,  Migration. — How  and  why  done?  Ex- 
amples?    When? 

13.  Degeneration. — What  evidence  do  you  discover  of  degenerate  am- 
phibians?    Examples?     Purpose  of  this  degeneration  to  the  amphibian? 

14.  Poison. — Name  amphibians  of  a  poisonous  nature,  like  the  toad. 
Purpose  of  this  poisonous  secretion? 

In.  Naked  Skin. — How  do  you  account  for  the  naked  skin  of  the  am- 
phibians, while  the  other  classes  of  chordates  have  a  covering  such  as 
scales,  feathers,  or  hair? 


REPTILES    IN    GENERAL  405 

16.  Color  and  Color  Changes  in  Amphibians. — Purpose?  Find  an  ex- 
ample of:  (1)  warning  color;  (2)  alluring  color;  (3)  protective  color;  (4) 
terrifying  attitude.  Why  does  the  toad  .swell  up  so  big  when  you 
molest  it? 

17.  Animal  behavior  of  this  class.  Compare  with  other  chordate  classes. 
See  Laboratory  Guide,  pp.  12-16. 

18.  Dispersal. — Compare  with  the  geographic  distribution  of  other 
chordate  cla.s.ses.  Which  has  the  best  dispersal,  and  why?  The  least  dis- 
persal, and  why? 

19.  Barriers. — Compare  the  barriers  of  Amphibia  with  the  barriers  of 
other  chordate  classes.  What  class  has  the  most  barriers?  The  least 
number  of  barriers,  and  why?     Barriers  animate  an'd  inanimate? 

20.  Dominance. — The  number  of  Amphibia  now  is  only  one-eighth  that 
of  fishes,  one-fourth  that  of  reptiles,  and  one-tenth  that  of  birds.  Were 
amphibians  ever  a  dominant  class?  Why?  Are  they  now  at  a  disadvan- 
tage in  the  race  of  life  as  compared  with  other  chordate  classes?  If  so,  why? 
Have  amphibians  sought  safety  in  subordination?  Will  they  ever  do  so? 
Compare  all  degenerate  chordates.  Have  they  sought  safety  in  subor- 
dination?    Why? 

21.  Preparedness. — Which  of  the  chordate  classes  has  the  best  pre- 
paredness for  dispersal?  The  least?  Which  class  has  the  best  prepared- 
ness to  overcome  barriers?     The  least? 

22.  Which  chordate  class  has  the  best  preparedness  to  be  a  dominant 
class?     Preparedness  in  what  ways  do  you  mean? 

REPTILES   IN    GENERAL 

1.  Covering. — Covering  by  orders.  Variations  in  the  different  orders? 
Why  this  variation? 

2.  Defense. — Give  examples  of  reptilian  defense  by:  (1)  terrifying  ap- 
pearance; (2)  noi.se;  (3)  bluff;  (4)  color;  (.5)  concealment?  How  are  the 
young  protected?     The  eggs? 

3.  Colors. — Find  an  example  of:  (1)  colors  for  protective  resemblance; 
(2)  warning  colors;  (3)  terrifying  colors;  (4)  mimicry.  (Fig.  198.)  Fur- 
pose  of  these  colors  to  the  reptiles? 

4.  Sounds. — Name  reptiles  that  hiss,  rattle,  bellow,  or  make  other 
sounds  or  noises.     Purpose  of  these  sounds  or  noises  to  the  reptile? 

5.  Locomotion. — Name  reptiles  that  crawl,  creep,  walk,  run,  fly,  swim, 
or  have  other  means  of  locomotion. 

0.  Degeneration.— Head  in  your  geology  of  tlie  reptilian  monsters  of  the 
pa.st  ages.  How  would  you  account  for  rejitilian  degeneration?  Will  the 
reptilian  class  ever  regain  its  lost  dominance? 

7.  Dominance  of  Reptiles. — Compare  with  other  classes  of  chordates. 


406  QUESTIONS,    PROBLEMS,    AND    SUGGESTIONS 

8.  Enemies. — Name  all  eneinios  of  r(>i)tik'.s  of  the  adult,  stage,  of  the 
young,  or  of  the  eggs. 

9.  Name  reptiles  that  migrate;  that  hibernate;  that  estivate.  When? 
Where?     How  long?     Purpose? 

10.  Economics. — Value  commercially  or  scientifically  as  compared  with 
other  classes  of  chordates? 

11.  Interest  to  you,  as  compared  with  other  classes  of  chordates? 

12.  Dispersal. — Name  all  their  means  of  dispersal. 

13.  Barriers. — Name  all  the  barriers  to  the  dispersal  of  reptiles. 

14.  Why  is  the  reptilian  disposition  or  character  more  disUked  than  that 
of  any  other  class  of  chordates?  Has  their  race  environment  or  their  race 
heredity  made  them  so? 

15.  Read  Ditmars'  "The  Reptiles  of  the  World"'  and  get  his  viewpoint, 
which  is  le.ss  hostile.  Why  do  we  fear  reptiles?  Is  it  hereditary?  Do 
other  animals  fear  snakes  or  reptiles  in  general? 

ORDER   OPHIDIA 

16.  How  do  you  account  for  the  limbless  condition  of  snakes?  How  and 
why  can  a  snake  coil?     How  strike? 

17.  Degeneration. — What  caused  the  degeneration  of  snakes?  Will  they 
become  extinct?  Why?  Were  they  ever  lizards,  or  are  they  just  degen- 
erate lizards? 

18.  Subordinalion. — What  causes  some  animals  to  seek  safety  in  subor- 
dination?    Results?     Name  examples  from  each  chordate  class. 

19.  Mimicry. — How  do  you  account  for  mimicry  in  some  snakes?  (See 
p.  242  of  the  text.)     Is  it  a  sure  means  of  defense? 

20.  Account  for:  (1)  the  bright  colors  of  some  snakes;  (2)  the  somber, 
or  dull  ones;  (3)  the  rattles  of  rattlesnakes;  (4)  the  "blow"  of  the  "blow 
viper";  (5)  some  snakes  being  poisonous.  Advantages?  Disadvantages? 
Why  are  the  poi.sonous  ones  becoming  extinct,  while  the  non-poisonous  ones 
(e.  g.,  the  common  garter  snake)  remain? 

21 .  What  is  the  secret  of  a  snake  charming  a  bird?  Has  fear  on  the  part 
of  the  bird  much  to  do  with  it?      Is  it  paralysis  of  fear  on  the  bird's  part? 

22.  How  and  why  do  snakes  get  their  prey  as  they  do?  Why  do  they 
swallow  it  whole? 

23.  Enemies  of  Snakes.— Of  the  adult?     Of  the  young?     Of  the  eggs? 

24.  Self-defense  of  snakes,  their  young,  or  their  eggs.  Name  three 
means  of  snake  defense. 

2').  Compare  a  snake  and  a  frog  as  aberrant  forms  of  their  classes. 
Are  both  degenerate  or  aberrant  examples  of  their  classes?  Causes? 
What  does  the  word  "snake"  mean? 

2G.  Name  one  special  body  characteristic  of  a  snake;  one  mind  charac- 
teristic? 


REPTILES    IN    GENERAL  407 

LACERTILIA  OR  LIZARDS 

27.  Variaiion. — Note  variation  in  form,  size,  and  appearance  of  lizards 
figured  in  the  text. 

2S.  The  Helodcrma  (Fig.  200). — How  account  for  it.s  poisonous  nature 
and  its  limited  geographic  distribution?  Can  you  name  other  poisonous 
lizards?     Is  it  a  dominant  reptile?     Why? 

29.  The  Chameleon  (Fig.  202). — How  account  for  its  power  of  changing 
colors?     Purpose  of  this  to  the  chameleon? 

30.  The  Horned  Toad  (Horned  Lizard,  P'ig.  203). — How  account  for  its 
structure,  appearance,  and  habits? 

31.  Where  do  you  find  the  large  lizards?  (p.  248).  The  small  ones? 
(p.  247). 

32.  Hibernation,  estivation,  and  migration  of  lizards.     Ciive  examples. 

33.  The  Monitor  of  the  Nile  (p.  248).— Why  is  it  a  friend  to  the  Egyp- 
tians? 

34.  Food. — What  lizards  are  used  by  man  for  food?  (p.  248). 

35.  Comparison. — Compare  lizards  and  salamanders  on  ten  points  of 
comparison  of  your  own  choosing.  Which  ones  do  you  consider  have  the 
more  complex  body,  the  lizards  or  the  salamanders?  Which  show  more 
manifestations  of  mind?     Less? 

36.  Size. — Are  lizards  large,  medium,  or  small-sized,  as  reptiles?  As 
chordates? 

37.  Dominance. — Are  lizards  dominant  or  superior  as  an  order  of  their 
class?     Why? 

CHELONIA  OR  TURTLES 

38.  The  Shell. — What  causes  or  conditions  gave  rise  to  the  shell?  Ad- 
vantages? Disadvantages?  Will  the  shell  lead  to  an  advance  or  a  degen- 
eration for  the  turtle's  order? 

39.  Degeneration. — How  do  you  account  for  the  present-day  turtle's  de- 
generation, as  compared  with  the  turtles  of  former  geologic  times?  Will 
turtles  become  extinct?  Why?  How  do  you  account  for  the  size  and 
habits  of  the  turtles  named  on  pp.  2,52,  253  of  the  text? 

40.  Teeth. — How  do  you  account  for  the  absence  or  loss  of  teeth  in  the 
turtle  order?     How  are  they  compensated  for  the  absence  of  teeth? 

^l.- Aberrant  Type. — Is  the  turtle  the  most  aberrant  reptile  of  its  cla.ss? 
Compare  the  turtle  and  toad  as  aberrant  chordates.  Are  snakes  and 
turtles  aberrant  or  degenerate  examples  of  their  clas.ses? 

42.  Noise.— Whiit  noise  does  the  turtle  make?  When?  Why?  What 
bird  makes  a  similar  noise? 

43.  Defense.— Note  how  it  strikes.  What  other  rei)tile  strikes?  What 
reptiles  bite? 

44.  Dominance. — Are  turtles  a  dominant  reptilian  order?  Why?  Were 
they  ever  a  dominant  reptiUan  order? 


408  QUESTIONS,    PROBLEMS,    AND    SUGGESTIONS 

CROCODILIA 

45.  How  account  for  the  powerful  head,  the  stout  linibs,  and  the  strong, 
compressed  tails  of  alligators  and  crocodiles? 

46.  Why  are  they  aquatic  and  nocturnal?  Their  prey?  How  and  when 
secured? 

47.  Why  do  they  hibernate  in  temperate  climates?  Why  migrate  or 
estivate  in  dry,  tropical  regions? 

48.  Compare  the  gavial,  alligator,  crocodile,  and  caiman  in  head.  body, 
tail,  and  limbs. 

49.  Commercial  value  of  any  of  the  Crocodilia? 

50.  Why  are  crocodiles  fast  becoming  extinct? 

AVES 

1.  Feathers. — What  is  a  feather?  Name  kinds,  arrangement,  colors, 
and  uses  to  birds  and  to  man. 

2.  Are  feathers  analogous  or  homologous  structures  with  scales  of  fishes 
and  reptiles,  and  with  the  hair,  fur,  or  wool  of  mammals? 

3.  How  account  for  feathers  for  birds?  Do  any  have  some  scales? 
Give  examples.     Feathers  for  flight  or  warmth? 

4.  The  Flight  of  Birds. — Do  their  feathers,  their  peculiar  respiration 
(p.  267),  and  their  high  temperature  (p.  267)  correlate  for  flight?  What  is 
flight?     In  what  does  it  consist? 

5.  Why  are  birds  the  most  successful  "flying  machines"?  Does  suc- 
cess indicate  superiority?  If  so,  in  what  are  fishes,  amphibians,  reptiles, 
and  mammals  superior? 

6.  Observe  Figs.  209,  210,  and  212.  Do  you  discover  any  reptilian 
affinities?  Scientists  claim  birds  have  evolved  from  a  reptilian-like  an- 
cestry.    Give  your  reasons  for  or  against  their  claim. 

7.  Colors. — Name  birds  with  alluring  colors;  with  colors  for  protective 
resemblance.     Do  birds  ever  change  colors?     If  so,  when  and  why? 

8.  Defense. — Name  all  the  ways  and  mean  spossessed  by  birds  either 
directly  or  indirectly  for  self-defense  or  for  the  defense  of  their  young  or 
their  eggs. 

9.  Enemies. — Make  a  list  of  all  enemies,  both  animate  and  inanimate, 
that  are  detrimental  to  birds,  their  young,  or  their  eggs.  In  spite  of  this 
formidable  list,  why  are  birds  a  dominant  class  of  chordates? 

10.  Migration. — Give  facts  and  theories  of  bird  migration.  Do  any  birds 
hibernate?     Remain  active  over  winter? 

11.  Economics. — Begin  with  the  ostrich  and  report  a  list  of  50  birds  of 
domestic,  scientific,  or  commercial  value  to  man. 

12.  Nests. — Report  on  all  kinds  of<  materials  used  for  nests,  where  built, 
when  built,  why  built,  number  of  eggs  in  "clutch"  for  each  kind  named, 
time  for  incubation,  care  of  young,  and  number  of  broods  for  each  season. 


MAMMALIA  409 

13.  What  is  a  nest?  Have  amphibians,  fishes,  reptiles,  and  mammals 
anything  that  corresponds  to  a  nest?  If  so,  what  is  it  called?  How  made? 
When?     Why?     When  used? 

14.  Intelligence  of  Birds. — Compare  with  other  classes  of  chordates;  as 
a  class. 

15.  Habitat  of  Birds. — Name  some  birds  that  are:  (1)  aerial  (most  of 
the  time);  (2)  aquatic;  (3)  arboreal;  (4)  terrestrial;  and  (5)  subterranean. 
What  conditions  have  brought  about  these  various  habitats? 

16.  Rivalry. — Name  examples  of  rivalry:  (1)  by  battle;  (2)  by  song;  and 
(3)  by  color  among  birds. 

17.  Parasites. — Name  internal  and  esternal  parasites  of  wild  birds;  of 
domesticated  ones.  Name  birds  that  are  parasites.  (See  p.  302,  The 
Cowbird.)     Do  you  know  of  others? 

18.  Animal  Behavior. — ^See  Laboratory  Guide,  p.  12,  and  report  on  the 
bird's  behavior,  points  1-9. 

19.  Compare  the  bird  and  reptile  on  points  1-9.  Which  shows  the  more 
animal  behavior? 

20.  Bird  Pests. — Do  birds  ever  become  a  nuisance  or  a  pest?  For  ex- 
ample, the  English  sparrow.  Give  others.  Do  birds  carry  parasites  or 
disease?     How  guard  against  them? 

21.  Bird  Pets. — What  birds  are  used  for  pets?     What  was  falconry? 

22.  Domestication. — What  birds  are  now  or  have  been  domesticated  by 
man?     For  what  use? 

25.  Dispersal. — Name  all  means  of  dispersal  by  birds,  their  yoimg,  or 
their  eggs. 

24.  Barriers. — Name  all  barriers  to  bird  dispersal. 

25.  The  Character,  or  Disposition  of  Birds. — Compare  with  other  chor- 
date  classes,  the  reptiles,  for  example. 

26.  Which  was  first  in  time,  the  bird  or  the  egg?  Give  your  reasons  care- 
fully? 

MAMMALIA 

1.  Covering. — Name  the  kinds  of  covering  of  mammals  and  state 
their  uses  to  the  mammal  and  to  man. 

2.  Scales. — Name  mammals  that  possess  scales,  c.  g.,  the  tail  of  a  rat. 
Name  other  examples. 

3.  Teeth. — Name  and  describe  the  four  kinds  of  teeth  possessed  by 
mammals  and  state  the  use  of  each  kind  in  the  digestion  or  life  of  the 
mammal. 

4.  In  what  orders  of  mammals  do  you  find  claws,  nails,  hoofs,  horns? 
Purpose  of  each  to  the  mammal? 

5.  Glands  of  Mammals. — Sebaceous  (oil),  sudoriferous  (sweat),  lachry- 
mal (tear),  scent,  and  mammary  glands  are  all  modified  cutaneous  glands. 


410  QUESTIONS,    PROBLEMS,    AND    SUGGESTIONS 

Name  examples  of  mammals  with  these  glands.  Uses  of  each  to  the 
mammal?  Compare  the  glands  of  mammals  with  the  glands  of  other  chor- 
date  classes.     Name  internal  glands  of  mammals. 

6.  Take  questions  7-27  under  Birds,  making  necessary  changes  in  the 
questions  to  fit  mammals. 

28.  "Mammals  are  supposed  to  have  originated  from  some  early  rep- 
tihan  animal  and  branched  off  long  before  the  birds  were  evolved" 
(American  Animals,  by  Stone  and  Cram).  State  your  idea  of  the  make-up 
of  this  primitive  reptilian  ancestor  of  mammals. 

29.  Give  your  idea  of  a  primitive  mammal  from  which  may  have  evolved 
the  mammahan  orders  of  today. 

30.  What,  then,  is  the  line  of  descent  of  chordates?  Was  it  fish-like, 
amphibian-hke,  reptilian-Hke  to  primitive  mammal,  with  birds  as  an  off- 
shoot from  some  reptilian-like  ancestor?  Wnat  was  the  general  structure 
and  make-up  of  a  primitive  chordate?     (See  Fig.  152.) 

31.  Order  I.  Primitive  Mammals. — Does  the  egg-laj'ing  habit  show 
primitive  condition?  The  "mammary  pouch"?  The  cloaca?  Hegner 
says:  "In  certain  respects,  the  skeleton  agrees  with  that  of  the  reptiles." 
Would  this  show  reptilian  affinities? 

The  Duck-bill. — Note  its  bill.  For  what  use  are  the  strong  front  toes? 
Use  of  the  duck-bill's  tail?  Habitat  of  the  duck-bull?  Why  is  this  order 
not  a  dominant  one? 

32.  Order  II. — Show  how  these  primitive  mammals  are  in  advance  over 
Order  1  in  the  condition  of  the  young.  Their  peculiar  mode  of  locomotion? 
From  the  mode  of  life  and  the  structure  of  this  order,  would  it  be  a  domi- 
nant order  if  placed  in  contact  with  order  Carnivoraf  Why  are  the  animals 
of  this  order  so  restricted  in  their  geographic  distribuition?  Why  is  the 
opossum  so  widely  distributed  as  compared  with  other  members  of  this 
order? 

33.  Order  V.  Cetacea. — How  do  you  account  for  the  "blubber"  of  the 
whale?  The  baleen?  The  hairless  skin?  Vestigial  limbs?  Horizontal 
tail  as  the  chief  organ  of  locomotion?  Was  the  whale  ever  a  terrestrial 
animal?  If  so,  what  changed  it  to  an  aquatic  one?  What  is  a  whale?  Its 
commercial  value  as  compared  with  the  old  days  when  whahng  was  a 
buisness? 

34.  Order  VI.  Ungulata. — What  are  the  hoofs  of  this  order?  Horns? 
Does  any  other  order  of  mammals  possess  horns?  Herbivorous  or  car- 
nivorous? Special  means  of  defense?  Teeth  in  this  order?  Name  un- 
gulates domesticated  by  man.  Uses?  Ungulates  of  special  curiosity? 
(p.  343). 

Why  are  ungulates  a  dominant  order?  Name  their  chief  chordate  enemy; 
their  principal  invertebrate  enemies. 

35.  Order  VII.    Rodentia. — Teeth   of  this  order?      Why  no   canines? 


MAMMALIA  411 

P 
Voice?     Defense?     Useful  rodents?     Harmful  ones?     Why  is  it  a  domi- 
nant order  of  mammals? 

36.  Order  VIII.  Carnivora  or  Mammals  of  Prey. — This  order  illustrates 
the  adaptation  of  structure  to  liabits.  Note  the  sharp  claws,  canine  teeth 
fitted  for  tearing,  and  the  alertness  of  the  Carnivora.  Why  are  the  Carniv- 
ora a  dominant  order?  What  ones  furnish  furs?  Name  some  high-priced 
mammalian  furs.  Do  any  furnish  food  for  man?  Make  a  list  of  all 
Carnivora  named  in  the  text  and  state  the  use  or  harm  of  each  to  man  and 
other  animals. 

37.  Order  IX.  Insectivora. — Why  long-snouted?  Nocturnal?  Self- 
defense?  Food?  Where  are  they  in  winter?  Note  the  adaptation  of  the 
mole  to  a  subterranean  life — pointed  head,  digging  feet,  and  fine,  soft  fur. 

The  Shrew. — Compare  with  the  mouse  as  to  general  appearance  and 
show  from  the  teeth  that  the  shrew  is  not  a  rodent.  What  ones  of  this 
order  hibernate?  Why?  Is  hibernation  correlated  with  their  food?  What 
ones  are  useful  to  man?     Harmful?     Why  is  this  order  not  a  dominant  one? 

38.  Order  X.  Chiroptera.  The  Bats.— Why  nocturnal?  Why  hiber- 
nate? Specialty,  zigzag  flight.  How  and  why  zigzag?  Note,  their 
extreme  sensitivity  makes  them  such  expert  flyers  in  the  dark.  Compare 
their  wings  with  the  wings  of  a  bird.  Food  and  feeding  habits?  Use  and 
harm  to  man?  Self-defense  and  sleeping  habits?  Why  of  interest  as  a 
"flying  mammal"? 

39.  Order  XI.  Primates. — Leave  man  out  and  how  do  the  other  animals 
of  this  order  compare  in  use  or  harm  to  the  Ungulata,  Rodentia,  and  Car- 
nivoraf  But  include  man;  then  what?  They  are  very  much  like  man  in 
their  structural  development.  Whence  came  monkeys  and  man?  From 
the  same  primitive  stock,  or  from  a  different  ancestry?  Is  there  a  "missing 
link"?  If  so,  what  is  it?  Missing  between  what?  For  a  study  of  man, 
see  Laboratory  Guide,  pp.  222-224. 

40.  Name  .some  mammalian  pests  and  pets;  some  domesticated  ones. 

41.  Dominance. — Why  is  Mammalia  a  dominant  class? 

42.  Man. — Why  is  man  the  most  successful  dominant  being  on  earth?    ' 

43.  CivilizaHon. — (Define  it.)  Has  man's  civilization  changed  more  than 
his  heredity  or  his  environment?  Can  you  change  the  heredity  of  an 
animal  or  of  man?     Can  you  change  an  animal's  inheritance? 

44.  Are  normal  animals  governed  more  by  heredity  or  environment? 
Abnormal  ones? 

45.  What  would  you  give  as  your  final  summary  of  the  animal  kingdom? 
How  does  it  interest  you?  Why  study  it?  What  would  this  world  be 
without  animals?  (You  may  suppose  man  exists.)  How  differ  from  his 
present  state  without  animals?  Without  plants,  but  with  animals?  With 
plants,  but  without  animals? 


412  QUESTIONS,    PROBLEMS,    AND    SUGGESTIONS 


ANIMALS  OF  ECONOMIC  INTEREST  OR  VALUE  TO  MAN 

See  Text,  pp.  4,  9,  14,  15,  16,  32,  35,  36,  37,  38,  39,  42,  43,  55,  62,  66,  70, 
72,  75,  76,  79,  80,  85,  93,  94,  99,  101,  103,  105,  109,  120,  125,  130,  131,  135, 
137,  140,  141,  142,  143,  145,  146,  147,  150,  151,  152,  154,  155,  156,  157,  158, 
159,  162,  165,  166,  167,  169,  170,  173,  175,  176,  180,  182,  185,  among  the 
Invertebrates. 

Among  the  Chordates,  pp.  197,  203,  205,  210,  211,  213,  215,  216,  222, 
235,  242,  244,  252,  255,  257,  269,  270,  272,  279,  280,  etc.,  through  Birds 
and  Mammals.  Student  complete  the  page  references,  then  prepare  a 
named  hst  of  100  animals  of  economic  or  commercial  interest  to  man. 
Do  you  discover  that  animals  enter  much  into  the  Environment  of  our 
lives?  Try  a  list  of  100  Plants.  Organic  Life  is  one  of  the  big  factors  of 
our  Environment. 


GLOSSARY 

Agamically.     Without  fertilization. 

Altricial.     Hatched  in  a  helpless  condition,  being  wholly  dependent  upon 
the  care  of  the  parent. 

Analogous.     Similar  in  function. 

Ankylose.     To  consolidate  or  grow  two  bones  into  one. 

Anthropologist.     One  versed  in  the  science  of  the  structure  and  function 
of  the  human  body  or  the  development  of  the  human  race. 

Apodal.     Having  no  feet. 

Atrophy.     The  wasting  away  or  degeneration  of  an  organ. 

Biramous.     Consisting  of  two  branches. 

Callosities.     Spots  of  hard  and  thickened  skin. 

Caviare.     The  roes  of  sturgeons,  salted  and  prepared  for  food. 

Commensalism.     The  association  of  two  species  of  organisms,  where  one, 
at  least,  is  benefited  and  the  other  not  perceptibly  injured. 

Crepuscular.     Feeding  in  the  dusk  or  before  sunrise. 

Degeneration.     The  substitution  of  a  lower  for  a  higher  form  of  struc- 
ture, the  hereditary  deterioration  of  type. 

Diastema.     An  intervening  space,  especially  between  the  teeth. 

Dimorphism.     "The  condition  of  the  appearance  of   the  same  species 
under  two  dissimilar  forms." — Darwin. 

Distal.     Away  from  the  place  of  attachment  to  the  body. 

Diurnal.     Active  or  feeding  by  day. 

Diverticulum.     A  blind  tube  branching  out  of  a  longer  one. 

Estivate.     To  pass  the  summer  in  a  state  of  torpor. 

Gregarious.     Many  individuals  of  one  species  banding  or  herding  together 
for  mutual  protection. 

Gular.     Pertaining  to  the  gula  or  throat. 

Hermaphroditism.     The  possession  of  both  male  and  female  reproductive 
organs  by  the  same  individual. 

Heterocercal.     Having  an  unequally  divided  tail  or  caudal  fin. 

Histolysis.     Disintegration  or  dissolution  of  organic  tissue. 

Homocercal.     Having  the  caudal  fin  symmetric  as  to  its  lobes  or  halves. 

Homogeneous.     Alike  throughout,  having  parts  of  only  one  kind. 

Homoiothermal.     Having  a  uniform  temperature  unaffected  by  environ- 
ment. 

Homologous.     Similar  in  structure  or  origin. 

4i3 


414  GLOSSARY 

Irritability.     That  power  or  property  by  which  an  organism  is  able  to 

respond  to  stimuli. 
Littoral.     Pertaining  to  the  shore. 

Lophophore.     A  disk  which  surrounds  the  mouth  and  bears  the  tentacles. 
Medusoids.     Medusa-like  structures. 
Metabolism.     The  process  by  which  food  is  built  up  into  living  tissues, 

and  living  material  broken  up  into  simpler  products  in  an  organism  or 

cell. 
Milt.     The  spermatic  fluid  of  fishes. 
Myrmecophilous.     Living  with  ants,  said  of  insects  which  inhabit  the 

formicaries  or  nests  of  ants. 
Natural  selection  "implies  that  the  individuals  which  are  best  fitted  for 

the  complex  and,  in  the  course  of  ages,  changing  conditions  to  which 

they  are  exposed  generally  survive  and  procreate  their  kind." — Darwin. 
Nocturnal.     Feeding  or  becoming  active  in  the  night. 
Omnivorous.     Eating  both   animal   and   vegetable   food,    feeding   indis- 
criminately. 
Ontogeny.     The  development   of  an  individual   organism   from   its   in- 

cipiency  in  the  egg  to  the  adult  state. 
Operculum.     A  lid-shaped  structure  closing  the  aperture  of  a  tube  or 

shell. 
Ovoviparous,  Viviparous.     Hatching  the  eggs  within  the  parent  body,  or 

bringing  forth  living  young. 
Parthenogenesis.     Reproduction  by  supposedly  unfertilized  eggs. 
Pendactyl.     Having  five  digits. 
Pentameral.     Arranged  in  fives. 
Philogeny.     The  study  of  the  ancestry  of  organisms,  or  the  history  of 

the  race. 
Placenta.     The  vascular  membrane  which  connects  the  embryo  with  the 

mother  and  supplies  it  with  nutriment. 
Poikilothermal.     Having  a  body  temperature  varying  with  that  of  the 

environment. 
Polymorphism.     The  condition  of  having  many  forms. 
Precocial.     Able  to  run  about  when  hatched. 
Proximal.     Near  the  place  of  attachment  to  the  body. 
Pseudopodium.     Any  protoplasmic  protrusion  from  a  unicellular  organ- 
ism. 
Recognition  Mark.     Coloration  of  special  parts  by  which  the  members  of 

one  species  may  recognize  their  own  kind,  particularly  beneficial  in  the 

recognition  of  parents  by  the  young. 
Reversion.     A  return  toward  a  recent  ancestral  type  or  character. 
Rheotropism.     The  directive  influence  upon  growth  exerted  by  currents 

of  water  or  air. 


GLOSSARY  415 

Roe.  The  ova  or  spawn  of  fishes  and  amphibians,  especially  when  still 
inclosed  in  the  ovarian  membranes. 

Rudimentary.     In  an  early  stage  of  development. 

Sarcode.  The  gelatinous  material  forming  the  bodies  of  sponges  and  other 
low  animal  forms. 

Somites.     The  segments  of  which  an  articulated  body  is  composed. 

Stomodeum.  The  primitive  mouth  and  esophagus  found  in  actinozoans 
and  in  the  embryos  of  annelids  and  arthropods. 

Symbiosis.  The  living  together  of  two  species  of  animals  or  plants,  inti- 
mately and  permanently,  to  their  mutual  advantage. 

Syndactylous.  Having  the  toes  united  for  some  distance,  but  without  a 
web. 

Trochosphere.  That  larval  form  of  various  worms,  mollusks,  and  mol- 
luscoids  which  has  a  circlet  of  cilia. 

Vestige.  A  structure  of  the  past  left  behind;  a  degenerate  organ  or  struc- 
ture. 


INDEX 


Abomasum,  337 

Acanthocephala,  44 

Acanthopteri,  215 

Acarina,  108 

Acephala,  73 

Achromatin,  383 

Acrania,  194 

Acrididse,  137,  138 

Actinophrys,  9 

Actinozoa,  26 

Adaptation,  wings  of  birds,  263 

^^gialitis  vocifera,  291 

Agalenidse,  106 

Aglossa,  73,  233 

Agonoderus  pallipcs,  151 

Alaudidse,  301 

Alces  americanus,  342 

Aletia  argillacea,  167 

Alligators,  253,  254 

Alluring  colors  of  insects,  118 

Alopias  vulpes,  205 

Alternation  of  generations,  8,  22 

Alytes  obstetricans,  226 

Amblyopsidse,  214 

Amblystoma  pundatum,  232 

Amoeba  terricola,  1 

Ampelidse,  304 

Amphibia,  221 

Amphioxus,  190,  194 

Ampullae,  53 

Anacanthini,  214 

Andrenid®,  183 

Anguillida;,  213 

Anis,  298 

Annulata,  65 

Anolis,  247 

Anomia,  74 

Anopheles,  4,  156 

rossii,  157 
Anosia  plexippus,  118,  171 
Anseres,  285 
Ant-eater,  319,  321,  324 
27 


Antelopes,  345 
Anthrenus  scrophularicF,  153 
Anthropoid  apes,  375 
Anthropoidea,  372,  373 
Anthropopithecus  erectus,  379 
Antilocapra  americana,  344 
Ants,  174,  177 

agricultural,  180 

carpenter,  179 

communism  of,  179 

corn-louse,  180 

intelligence  of,  180 

mound-building,  179 

slave-making,  179 
Anura,  224,  228 
Aphidida?,  140 
Aphides,  124 
Aphids,  143 
Apidae,  183 
Apis,  184 
Apoda,  228 
Aptera,  126 
Apteria,  259 
Arachnida,  103 
Araneida,  104 
ArchcBopteryx,  258,  369 
Arctomys  marmotta,  352 
Ardea  candidissima,  228 

egretta,  288 
Ariolimax  calif ornica,  83 
Aristotle,  386 
Armadillos,  324 
Aromochelys  odoraius,  253 
Arthropoda,  89 

classification  of,  186 
Arthrostraca,  102,  103 
Artiodactyla,  332,  334 
Ascaris  lumbricoides,  43 

nigrovenosa,  41 
Ascidians,  192 
Assimilation,  7 
Asterias  vidgaris,  54 

4]  7 


418 


Asteroidea,  54 
Atavism,  388 
Ateles,  374 
Attida;,  108 
Auk,  281 
Automatism,  7 
Aves,  258 

Babirusa,  335 
Badger,  360 

Baloenoptera  sibbaldii,  328 
Balanoglossus,  190,  191 
Baltimore  oriole,  302 
Barnacles,  91 
Bass,  215 
Bateson,  390 
Bats,  368,  371 
Bdelloida,  47 
Bears,  359 
Beavers,  353 
Bees,  174,  183 
Beetles,  carpet,  173 

ground,  151 

myrmecophilous,  153 

tiger,  150 

water,  152 
Belostomida;,  142 
Beluga,  328 
Bettongia,  323 
Bivalva,  73 
Blackbirds,  302 
Blastostyles,  22 
Blastula,  385 
Blattidae,  134 
Blind  fishes,  214 
Blissus  leucoptcrus,  142 
Blow-flies,  155 
Bombida;,  184 
Bombinator,  227 
Bombus,  184 
Bombyliidaj,  161 
Bos  bonasus,  348 

grunniens,  348 

primogenius,  348 

sivalensis,  350 
Bot-flies,  156 
Bothriocephahis  latus,  38 
Bovida;,  345 
Brachiopoda,  48 
Bradypodida?,  324 
Bradypus,  324 
Branchellion,  70 
Branchipus,  90 
Brine  shrimp,  90 


Buffalo  fishes,  212 
Buffon,  387 
Bt/fo  lentiginosus,  234 
Bufonida;,  234 
Butterflies,  162 

cabbage,  173 

distinguished  from  moths,  163 

gossamer-winged,  171,  173 

swallow-tailed,  172 


C^ciLiiD^,  229 
Calamistrum,  107 
Calamoichthys,  210 
Calasoma  scrutator,  151 
Calcarea,  16 
CalUnectes  sapidus,  101 
Camelida;,  337 
Camels,  337 
Camelus  badrianus,  338 

dromedarius,  338 
Campodea  staphylinus,  127 
Camponolus  pennsylvajiicus,  179 
Canidffi,  361 
Canis  lupus,  362 

occidentalis,  362 
Cankerworms,  165 
Capra  cegagrus,  345 

ibex,  345 

pyrenaica,  345 
Carabidse,  150 
Carapace,  90 
Caribou,  340 
Carinata;,  265,  281 
Carnivora,  356 

aquatiCj  365 

terrestrial,  358 
Carpocapsa  pomonella,  164 
Cassididse,  83 
Cassowary,  278,  280 
Castor  canadensis,  352 
Castoridse,  352 
Catarrhina,  375 
Cat,  domestic,  364 

family,  358 
Catfish,  212 
Cattle,  345 
Caudata,  229 
Caviare,  210 
Cavities,  hemal,  191 

neural,  191 
Cebida;,  373 
Cebus,  375 
Cecidomyiidse,  160 


INDEX 


419 


Cell,  division  of,  383 

polar,  385 

structure  of,  385 

theory,  382 
Centipedes,  111 
Centrosome,  383,  384 
Cephalopoda,  84 
Cephalothorax,  90 
Ceratina  dupla,  183 
Ceratodus,  209 
Cercarise,  36 
Cercopithecidae,  375 
Cercopithecina;,  375 
Certhiida;,  305 
Cervidaj,  339 
Cervus  canadensis,  340 
Cestoda,  37 

Cetacea,  312,  314,  315,  318,  326 
ChiBtognatha,  44 
Chaetopoda,  65 
Chamelion,  247 
Chamois,  346 
Chete,  95 
Chelonia,  248 
Chemotropism,  7 
Chevrotain,  337 
Chigoe,  162 
Chilopoda,  111 
Chimoera  moiistrosa,  207 
Chimpanzee,  377 
Chinch-bug,  140,  142 
Chiroptera,  368 
Chlamydophorus,  325 
Chotepus,  324 
Chondrostei,  210 
Chordata,  188 
Chromis,  212 
Chromosomes,  384 
Chrysemys  marginata,  253 
Chylema,  383 

Chylomyderus  geometricus,  204 
Cicada,  142  t 

Cicadidse,  142 
Cicindelida,  150 
Cilia,  5 
Cirri,  91 
Cirripedia,  91 
Cistudo,  253 
Civets,  365 
Clitellum,  68 
Clubionida?,  106 
Clytus  erictus,  175 
Cobweb-weavers,  107 
Coccidae,  140,  146 


Coccinellidae,  153 

Coccyges,  297 

Cockroaches,  134 

Codfish,  214 

Coelenterata,  17 

Coleoptera,  148 

Collembola,  127 

Color,  changes  of,  theories  of,  361 

Colubrida?,  243 

Columbse,  292 

Columba  livia,  293 

Commensalism,  14,  65,  100,  102 

Communism  of  ants,  179 

Condylura  cristola,  367 

Congo  snake,  231 

Conjugation,  8 

Contractile  vacuole,  2 

Contractility,  8,  13 

Coot,  289 

Copepoda,  91 

Coral,  secretion  of,  17 

stony,  29 
Cormorant,  285 
Corn-ear  worm,  167 
Corvidffi,  301 
Cossidae,  164 
Cotton-boll  worm,  167 
Cotton  worm,  167 
Cowbird,  302 
Cowries,  82 
Coyote,  363 
Crabs,  blue,  101 

fiddler,  102 

hermit,  100 

oyster,  102 

spider,  102 
Crane,  289 
Craniata,  195 
Crayfish,  90,  95 
Creepers,  305 
Cribellum,  107 
Crickets,  139 
Crinoidea,  62 
Crocodiles,  253 
Crocodilia,  253 
Crossopterygii,  210 
Crotalidae,  243 
Crows,  301 
Crustacea,  90 
Cryptobranchus,  231 

allegheniensis,  231 

japonicus,  231 
Ctenidia,  82 
Cteniza,  106 


420 


INDEX 


Ctenophora,  17 
Cuckoos,  298 
Culex,  156 

fatigans,  157 
Culicidae,  156 

Curled-thread  weavers,  107 
Cuttlefishes,  84 
Cyanea,  17,  26 
Cyclops,  91 
Cyclostomata,  195 
Cycloturus,  324 
Cynipidse,  176 
Cynocephalus,  375 
Cynomys,  352 
Cyprseidse,  82 
Cypress,  90 
Cysticercus,  38 
Cytoplasm,  383 


Dactylethra,  233 
Darwin,  Charles,  388 

Erasmus,  387 
Dasypodidae,  324 
Dasypus  sexcindus,  325 
Dasyuridae,  321 
Deer,  339 

DelphinidcB  elphineraptus,  328 
Dendrobates  tindorius,  227 
Dendrolagus,  322 
Dermophis,  229 
De  Vries,  390 
Diapheromera  fernorata,  137 
DictynidiB,  107 
Didelphidffi,  321 
Didelphys,  321 
Dimorphism  of  spiders,  106 

of  trochelminthes,  47 
Dinophilea,  47 
Dinosauria,  256 
Diodon  macidata,  204 
Diplopoda,  112 
Dipneumones,  106 
Dipnoi,  208,  220 
Dipodidae,  354 
Diptera,  153 
Dispersal  of  hydra,  20 

of  starfish,  55 
Dodo,  293 
Dolomedes,  108 
Dolphins,  328 
Dormice,  353 

Dracuncuhis  medinensis,  43 
Dragon-flies,  129 


Drassidse,  106 
Duck-bill,  320 
Dugong,  325 
Duplicidentata,  355 
Dyticida;,  152 


Eagles,  294 
Ear-shells,  82 
Earthworm,  65 
Ecaudata,  233 
Ecdysis,  227 
Echidna,  316 

aculeata,  319 
Echinodermata,  50 
Echinorhynchus,  44 
Economic  importance  of  annulates, 
70 

of  bats,  369 

of  birds,  305-309 

of  camels,  338 

of  caribou,  341 

of  cats,  365 

of  coelenterates,  32 

of  crustaceans,  99 

of  deer,  343 

of  fishes,  217-219 

of  hawks,  295 

of  hogs,  335 

of  horses,  334 

of  insectivores,  368 

of  insects,  125 

of  moUusks,  87 

of  nemathelminthes,  47 

of  platyhelminthes,  40 

of  protozoans,  9 

of  reindeer,  340 

of  reptiles,  257 

of  rodents,  356 

of  sponges,  14 

of  sturgeons,  210 

of  tapirs,  332 

of  whales,  329 

of  yak,  349 
Ectoderm,  17 
Ectopistes  migratorius,  293 
Ectoplasm,  2 
Edentata,  323 
Eels,  213 
Elapidai,  243 
Electrotropism,  7 
Elephant,  330 

mammoth,  331 
Elephantiasis,  157 


421 


Elephantidae,  330 
Elephas  africanus,  331 
Elephas  indicus,  331 
Elk,  340 
Elytra,  149 
Empedocles,  3.S6 
Emu,  280 
Encysting,  3 
Endoderm,  10,  17 
Endoplasm,  2 
Endopod,  90 
Entomostraca,  90 
Ephemerida,  127 
Epilachna  borealis,  153 
Epomophorus,  371 
Equida;,  334 
Erinaceus  europoeus, .  366 
Eristalis,  175 
Eumemes  fraternus,  181 
Eumenidae,  181 
Euplectella,  16 
Euspongia,  16 
Evolution,  386 
Exopod,  90 
Exoskeleton,  114 
Eye-color,  392 

Falconid^,  294 
Felidffi,  358,  363 
Felis  caffra,  364 

concolor,  364 

leo,  363 

maniculata,  364 

onca,  364 

pardus,  364 

tigris,  364 

uncia,  364 
Feniseca  taquinius,  173 
Fertilization,  385 
Fiber  osoyoosensis,  352 
Filiariasis,  157 
Fins,  pectoral,  ventral,  199 
Fish-moth,  127 
Fission,  8 
Fissipedia,  358 
Flagellum,  4 
Flat-worms,  34 
Fleas,  161 
Flesh-fly,  155 
Flies,  154-156 
Flounders,  215 
Fly-catchers,  301 
Formica  difficilis,  179 

cxsectoides,  179 


Formicidse,  179 

Foxes,  361 

Frigate,  285 

Fringillida;,  302 

Frogs,  236 

Funnel  web  weavers,  106 

Gall-flies,  175,  176 
Gall-gnats,  160 
Gallina;,  291 
Gallinago  delicata,  291 
Gallus  bankivus,  292 
Gammarus,  102 
Gar-pike,  211 
Gasteropoda,  81 
Gastrophilus  equi,  156 
Gastrotricha,.  47 
Gastrula,  386 
Gavial,  254 
Geese,  285 
Gemmules,  12 
Geomyidae,  354 
Geotropism,  7,  13 
Gephyrsea,  69 
Germ  plasm,  389 
Gibbons,  376 
Giraffes,  343 
Giraflid*,  343 
Glass-snake,  245 
Glires,  350 
Globigerina  ooze,  9 
Goats,  345 
Gonionemus,  26 
Gonium,  1 
Gonotheca,  22 
Gophers,  354 
Gordius,  44 
Gorgonacea,  31 
Gorillas,  378 
Grackles,  302 
Grantia,  116 
Graptolites,  32 
Grebe,  28 
Gregarina,  4 
Guinea- worm,  43 
Gull,  282 
Gymnodonta,  216 
Gymnophiona,  225,  228 


Hwmopsis  vorax,  70 
Haemosporidia,  4 
Hair-worm,  44 
Halictus,  183 


422 


INDEX 


Haliolidae,  82 
Hawks,  294 
red-tailed,  295 
sharp-shinned,  295 
Hedgehogs,  366 
Helicidae,  83 
Heliothis  armigera,  167 
Helix,  83 
Hellbender,  231 
Helmet-shells,  83 
Hemiptera,  138,  140 
Hepatic  caeca,  192 
Heredity,  388,  390 
Hermaphroditism   of  cirripedia, 
definition  of,  19 
of  holothuroideu,  62 
of  hydra,  19 
of  leeches,  69 
of  mollusks,  73 
of  porifera,  11 
Herodiones,  286 
Heron,  287 
Herpestes  griseus,  365 

ichneumon,  365 
Hessian  fly,  160 
Helerodera  schnchtii,  41 
Heterogeny,  40 
Heteroptera,  141 
Hippocampus,  204 
Hippopotamidaj,  334 
Hippotragus  niger,  345 
Hirudinea,  69 
Hirugo  sanguistiga,  70 
Hirundinidae,  304 
Hog,  335 
Holocephala,  207 
Holostei,  210 
Holothuroidea,  60 
Homoptera,  141 
Homo  sapiens,  379 
Honey  bee,  184 
Hooke,  382 
Hook-worm,  43 
Horned  hzard,  247 

toad,  247 
Hornets,  182 
Horn-tails,  175 
Horse,  334 
fly,  156 
House  fly,  154 
Humming  birds,  300 
Hyaenida>,  358,  365 
Hydra,  17 
viridis,  21 


91 


Hydractinea,  24,  25 
Hydroid,  21 
Hydro theca,  21 
Hydrozoa,  18 
Hyla  versicolor,  234 
HyHda},  234 
Hylobates,  376 
Hy lodes  liniatus,  226 
Hymenoptera,  174 
Hypoderma  lincala,  156 
Hypostome,  18 
Hyracida>,  329 
Hyrax,  329 

I  eery  a  purchasi,  153 
Ichneumonidae,  176 
Ichthyophis,  229 
Ichthyopterygia,  256 
Iguana,  248 
Incubation,  268 
Infusoria,  5 
Inquilines,  176,  184 
Insecta,  112 
Insectivora,  366 
Intelligence  of  ants,  ISO 

of  birds,  273 
Iphidides  ajax,  172 
Irritability,  7,  8,  13 
Isoptera,  131 
lulus,  112 
Ixodes,  110 

Jackals,  362 

Jays,  301 

Jennings,  on  ectoplasm,  3 

Jumping  mice,  354 

Kallima,  118 
Kangaroos,  322 
Katy-dids,  139 
Killdeer,  291 
Kingfishers,  297 
Kinosternida?,  253 

Labium,  133 
Labrum,  133 
Lacertilia,  243 
Lady-bugs,  153 
Lceiilia  coccidivora,  164 
Lamarck,  387 
Lamellibranchiata,  73 
Lampyridse,  153 
Lancelet,  190 


423 


Land  birds,  291 
Larks,  301 

Lasius  brunneus,  180 
Leibnitz,  387 
Lemuridse,  372 
Lemuroidea,  372 
Leopard,  364 

hunting,  365 
Lepas,  92 
Lepidoptera,  162 
Lepidosiren,  209 
Lepisma  saccharina,  127 
Lcpomis  cyanellus,  215 
Leporidaj,  250,  255 
Leptoplana,  34 
Lepus,  355 

americanus,  356 

aquaticus,  355 

campestris,  356 

palustris,  355 

sylvaticus,  355 
LibellulidEe,  129 
Life,  Archaean,  382 
origin  of,  382 
Limacidae,  83 
Limicolse,  290 
Limnaeus,  84 
Limpets,  82 
Limulus,  110 
Linckia  linckia,  56 
Lion,  363 
Lithobius,  111 
Littorina,  83 
Liver-fiuke,  36 
Llama,  339 
Lobster,  90,  99 
Locustidse,  138 
Locusts,  137 

seventeen-year,  143 
Longipennes,  282 
Loon,  281 

Lophobranchii,  212,  216 
Lophophore,  48 
Loris,  372 
Lutra,  359 
Lycoenidae,  173 
Lycostidae,  108 
Lymantriida?,  168 
Lynx,  364 


Macaques,  375 
Macheira,  102 
Mackerel,  215 


Macrochires,  300 
Macronucleus,  5 
Macropodida;,  322 
Macropus,  322,  323 
Madreporic  plate,  52 
Malacostraca,  90,  92 
Malpighian  tubes,  120 
Mammalia,  311 
Man,  379 
Manatee,  325 
Mantidae,  136 
Mantids,  praying,  136 
Marine  worms,  68 
Marmosets,  373 
Marmot,  352 
Marsupialia,  320 
Marten,  360 

Maryland  yellow-throat,  305 
Mastigophora,  4 
Maturation,  384 
Maxilla,  133 
Maxillary  palpus,  133 
May-flies,  127 
Medusae,  22 
Megachile  acuta,  183 
Megachiroptcra,  370 
Mekuniplus  olhnitis,  138 

fcmnr-ruhnnn,   137 

sprctus,  137 
Meleagrina,  77 
Meles,  360 
Melipona,  184 
Mendel's  law,  391 
Mephitis,  360 
Mesoderm,  386 
Mesoglea,  10,  17 
Mesothorax,  133 
Metabolism,  7 
Metamorphosis,  26 
Metathorax,  133 
Metazoa,  10 

Microchiroptera,  370,  371 
Micronucleus,  5 
Microtus,  353 
Migration,  274 
Millepora  alicornis,  25 
Millipeds,  112 
Milt,  212 
Mimicry  of  hymenoptera,  175 

of  insects,  il9 

of  viceroy,  172 
Mink,  360 
Mitosis,  383 
Mniotiltida;,  304 


424 


Mole,  367 

Australian,  322 
Mollusca,  72 
Molluscoida,  48 
Molting  of  crayfish.  98 
Monarch  butterfly,  172 
Mongoose,  365 
Monitors,  248 
Monkeys  of  America,  373 

Old  World,  375 

orang-utan,  376 

Saki,  374 

spider,  374 

squirrel,  374 
Monobia  quadridens,  181 
Monotremata,  319 
Moose,  342 
Morula,  385 
Mosquitoes,  156 
Moths,  162 

carpenter,  164 

coccid-eating,  164 

codling,  164 

gypsy,  169 

hawk,  170 

meal,  164 

owlet,  166 

tussock,  168 
Mud-eel,  229 

Multiplication,  sexual,  asexual,  11 
Murida;,  352 
Musca  domestica,  154 
Muscardinius  avellanarius,  353 
Muscidse,  154 
Mus  decumamis,  352 

minutus,  352 

musculus,  352 
Muskrat,  352 
Mustelida>,  359 
Mutation,  390 
Mya  arenaria,  SO 
Mydaus  milictes,  360 
Mygale,  106 
Myogale  moscata,  367 
Myriapoda,  111 
Myrmecophaga  jubata,  324 
Myrmecophagida?,  324 
Myrmicida",  180 
Mytilus,  74 

Nasalis,  375 
Natica,  83 

Natural  selection,  388 
Nauplius,  90 


Nautilus,  86 
Nebalia,  93 
Necrophorus,  150 
Necturus,  223,  231 
Nemathelminthes,  41 
Nematocysts,  19 
Nematoda,  41 
Nematus  ribesii,  175 
Nemertinea,  39 
Neotony,  232 
Nephridia,  68,  201 
Nereis,  69 
Newts,  232 

Nictitating  membrane,  271 
Night  hawk,  300 
Noctuida;,  166 
Non-ruminants,  334 
Notolrema  marsupiatum,  226 
Nucleoli,  383 
Nucleus,  2 
Nudibranchs,  83 
Nuthatches,  305 

Ocelli,  123 
Ocneria  dispar,  169 
Octocoralla,  31 
Octopus,  85 

Odocoileus  virginianus,  339 
Odonata,  129 
Odontoglossa>,  286 
Odor  of  bugs,  141 
CEstridffi,  156 
Oligocottue  snyderi,  198 
Omasum,  337 
Ophidia,  239 
Ophiopholis,  58 
Ophiuroidea,  56 
Orb  weavers,  107 
Orientation,  7 
Ornithorynchus,  320 
Orthogenesis,  390 
Orthoptera,  132 
Osculum,  10 
Ostracoda,  90 
Ostrea,  74 

edulis,  77 

virginiana,  77 
Ostrich,  278,  279 
Otaria  jubata,  365 

ursina,  365 
OtoHth,  203 
Otter,  359 
Ova,  384 

size  of,  384 


INDEX 


425 


Ovibos  moschatus,  348 
Oxwarbles,  156 
Oyster,  74 
drills,  83 

Palcemonetes  vulgaris,  99 
Paludicolae,  289 
Panther,  364 
Papilionidae,  172 
Parameles,  321 
Paramoecium,  5 
Parasita,  141 
Parasitism  of  birds,  276 
of  hymenoptera,  176 
of  insects,  124 
of  thyca,  56 
Parida;,  305 
Parr,  212 

Parthenogenesis,  124 
Passeres,  300 
Patagium,  258 
Patellida?,  82 
Pecten' irradians,  77 
jacoboeus,  77 
maximus,  77 
Pedicellariae,  54 

Peduncle,  48 

Pelecanus  calif ornicus,  285 
erythrorhynchus,  285 
fuscus,  285 

Pelecypoda,  73 

Pelican,  285 

Penguin,  281 

Pennatulacea,  31 

Pepsis  formosa,  181 

Perch,  215 

Perissodactyla,  332 

Periwinkle,  83 

Perlidffi,  128 

Petrel,  284 

Petrogale,  323 

Phalangerida?,  322 

Phalangidea,  104 

Phalaropes,  291 

Phaneroglossa,  234 

Pharaoh's  rat,  365 

Pharyngognathi,  212 

Phasmida;,  137 

Phasmomantis  Carolina,  136 

Philohela  minor,  291 

PhocidjB,  366 

Pholas,  8 

Phoronida,  48 

Phototropism,  7 


Phrynosoma,  247 
Phyllium,  118 
Phyllocardia,  93 
Phyllopoda,  90 
Phylloxera,  145 
Phylostoma  hastatum,  371 
Physa,  84 

Physeter  tnacrocephalus,  328 
Physterida^,  328 
Pici,  298 
Pieris,  173 
Pill-bug,  90,  102 
Pinnipedia,  365 
Pinnotheres,  76 
Pipa,  233 
Pipe-fish,  217 
Pisces,  196 
Pitheca,  374 
Planaria,  34 
Planorbis,  84 
Plasma,  383 
Platyhelminthes,  34 
Plalypsylla  castoris,  153 
Platyrrhina,  373 
Plecoptera,  128 
Plectognathi,  216 
Plover,  291 
Pluteus,  57,  60 
Pogonomyrmex,  180 
Polychetae,  68 
Polyergus  refescens,  179 
Polypterus,  210 
Polyzoa,  48 
Pond-snail,  83 
Poneridffi,  180 
Porcupines,  353 
Porpoises,  328 
Prairie-dog,  352 
Prawn,  99 
Primates,  372 
Proboscidea,  372 
Procamelus,  349 
Procyonidse,  358 
Prong-horn,  344 
Prostomium,  47 
Proteidje,  230 
Proteus,  225,  231 
Prothorax,  114 
Protoplasm,  1 

properties  of,  8 
Protopod,  90 
Protopterus,  206,  209 
Protovertebrates,  191 
,  Protozoa,  1 


426 


INDEX 


Protozoa,  malaria-producing,  4 

Pseudobranchus  striatus,  230 

Pseudopodia,  2 

Psithyrus,  184 

Psittaci,  297 

Pterosauria,  257 

Pterylse,  259 

Pulicidaj,  161 

Pulmonata,  83 

Puma,  364 

Putorius  fetidus,  360 

rixosus,  361 
Pygopodes,  281 
Pyralis  farinalis,  164 


Quail,  292 


Raccoon,  358 
Radiolaria,  3 

ooze,  9 
Raiidae,  206 
Rail,  289 
Rana  catesbiana,  236 

clamata,  236 
Rangifer  tarandus,  340 
Raptores,  294 
Rat  fleas,  162 
Ratitae,  265,  278 
Recurvirostra  americana,  291 
Reindeer,  340 
Remora,  210 
Reptilia,  236 
Resemblance,  protective,  of  bats,  370 

of  birds,  270 

of  crayfishes,  99 

of  flat-worms,  34 

of  geometrids,  165 

of  insects,  115 

of  pipe-fish,  217 

of  sea-cucumber,  61 

of  sea-urchin,  58 

of  weasel,  361 
special  protective,  kalliina,  118 

mantids,  136 

variable  protective,  118 

Rivalry  of  birds,  276,  292 

of  seals,  366 
Rock  wallabies,  323 
Rodentia,  350 
Rotifera,  46 
Round-worms,  41 
Ruminants,  336 


Saimiri,  374 
Salamander,  231 

maculosa,  227 
Salamandridse,  231 
Salmon,  213 
Salmonids,  213 
Sand-stars,  57 
Sand-worm,  69 
San  Jose  scale,  148 
Sarcode,  11 

Sarcophaga  sarracenioe,  155 
Sarcoptes  scabei,  110 
Sargassum,  198 
Sauropterygia,  256 
Saw-flies,  175 
Scale  bugs,  146 
Scales,  ctenoid,  198 

cycloid,  198 

ganoid,  197 

placoid,  197 
Scallop,  77 

Scalops  aquaticus  machrinus,  367 
Schleiden,  382 
Schools  of  fishes,  212 
Schwann,  382 
Sciuropterus,  352 
Sciurus,  352 
Scolopendra,  111 
Scombridse,  215 
Scorpanoids,  204 
Scorpionida,  103 
Scorpions,  103 
Sea-anemone,  27 
Sea-cucumber,  61 
Sea-horse,  217 
Sea-mussels,  84 
Sea-squirt,  192 
Seals,  365,  366 
Segmentation,  385 
Self-defense  of  amphibians,  226 

of  fishes,  204 

of  glass-snake,  246 

of  insects,  115 

of  snakes,  241 

of  turtles,  251 
Sesia,  175 
Setae,  67 

Sexual  selection,  389 
Sheep,  345,  347 

bot-fly,  156 
Shrimp,  99 
Silurids,  212 
Simiidffi,  375,  376 
Siphonaptera,  161 


427 


Sirenia,  312,  314,  325 
Sirenidse,  229 
Siren  ladertina,  229 
Siricidae,  175 
Skunks,  360 
Sloths,  324 
Slugs,  83 
Smolt,  212 
Snails,  83 
Snipes,  291 
Song  of  birds,  277 
Sorex  palustris,  366 

personal  us,  366 
Soricidae,  366 
Spermatozoon,  385 
Sphargis  coriacea,  252 
Sphecina,  181 
Sphendon  punctatum,  238 
Sphingidae,  170 
Sphynx  moth,  170 
Spider,  crab,  108 

ground,  106 

jumping,  108 

running,  108 
Sponges,  10-16 
Spongilla,  12 
Spongin,  11 
Spores,  4 
Sporocyst,  36 

Sporotrichum  globuliferum,  142 
Sporozoa,  4 
Sporulation,  3 
Squamata,  239 
Squid,  84,  85 
Squirrels,  351 

flying,  352 
Starfish,  50 
Steganopodes,  284 
Stegocephala,  228 
Stegomyia,  4 

fasciata,  157 
Stickleback  fish,  216 
Stilt,  291 
Stimulus,  7 

Stomodeum,  beginning  of,  26 
Stone  flies,  128 
Stork,  287 

Struggle  for  existence,  388 
"  Survival  of  the  fittest,"  388 
Swallow-tailed  butterflies,  172 

tiger,  172 

zebra,  172 
Swallows,  304 
Swan,  285 


Swift,  247,  300 

Sword-fish,  205,  216 

Symbiosis,  definition  of,  4 
Hydra  viridis  and  algoe,  21 
hydractinea  and  crab,  25 
pinnotheres,  76 
sponges  and  crab,  14 

Syngamus  trachcalis,  43 

Syrinx,  267 

Syrphida?,  161 

Syrphus  flies,  161 

Tabanid^,  156 
Taenia  echinococcus,  39 

saginata,  38 

solium,  37 
Tamandua,  324 
Tamaus  siriatus,  352 
Tanagers,  304 
Tapeworm,  37 
Tapirs,  332 
Tapirus  terrestris,  332 
Tasmanian  marsupials,  321 
Teidffi,  245 
Teleostei,  211 
Teleostomi,  209 
Teredo,  81 
Termites,  131 
Termitophily,  132 
Tern,  282,  283 
Terrapins,  252 

mud,  253 
Tessera,  26 
Testudinidffi,  253 
Tetrapneumones,  106 
Thalessa,  176,  177 
Thallassophryne,  204 
Theridiida;,  107 
Thermorpha,  256 
Thermotropism,  7 
Thigmotropism,  7 
Thomisidff,  108' 
Thrashers,  305 
Thrushes,  305 
Thysanura,  126 
Ticks,  110 
Tiger,  364 

Tinodera  sinensis,  136 
Tissues,  differentiation  of,  386 
Tolypeutes,  325 
Tortoises,  253 
Tracker,  365 
Tragulida^,  337 
Tree-frogs,  234 


428 


INDEX 


Trematoda,  35,  77 
Tremex  columba,  175,  176 
Trichechidae,  366 
Trichinella  spiralis,  41 
Trichinosis,  43 
Tridacna  gigas,  80 
Tritonidae,  83 
Tritons,  232 
Trochelminthes,  46 
Trochosphere,  68 
Troglodytidae,  305 
Trogon,  298 
Tube-weavers,  106 
Tubinares,  283 
Tunicata,  192 
Turbellaria,  34 
Turdida;,  305 
Turtles,  box,  253 

sea,  252 

soft-shelled,  252 

tortoise-shelled,  252 
Tylenchus  triHci,  41 
Tympanic  membrane  of  insects, 
Typhionectes,  229 
Typhlomolge  rathbuni,  231 
Typhlosole,  66 
Tyrannida;,  301 

Uloborid^,  107 
Ungulata,  329 
Urochorda,  192 
Urodela,  229 
Urosalpinx  cinerea,  83 
Ursidse,  359 

Vacuole,  3 
Vampires,  371 


123 


Varanus,  248 

niloticus,  248 
Vertebrata,  195 
Vespa,  182 
Vespertilionidse,  371 
Viceroy,  172 
Viverridae,  365 
Vorticella,  7 
Vulpes,  361 

Walking-sticks,  137 
Wallace,  388 
Warblers,  304,  305 
Warning  colors,  118 
Water  birds,  281 

bugs,  142 
Waxwings,  304 
Weasel,  360,  361 
Weismann,  389 
Whales,  326,  328 
Whip-poor-will,  300 
Whitman,  390,  391 
Wild  turkey,  292 
Wolf,  362 
Wombats,  322 
Wrens,  305 


XiPHOSURA,    110 


Yellow-fever  mosquito,  157 
Yellow-jackets,  182 


Zygote,  385 


